”I did it I did it I did it!" Zephyr Breeze giggled with glee, giddily trotting through the gates of Canterlot castle. He could hardly believe it himself, but he had managed to make it into the royal guard, narrowly making it through the written exam and technically passing the physical test too. Technically at least - he wasn’t exactly the pinnacle of masculine strength, but as long as he’d been approved it wasn’t like anypony would care of the little details. Besides, the guards job was going to be just standing around anyway.

After a little wandering, he managed to find the armory and retrieve his own personal armor. It wasn’t exactly a tight fit, but he figured it shouldn’t matter as long as the mares dig it. He was absolutely beaming with pride as he strode through the barracks and out to the castle courtyard.

As soon as he came out, he saw a line of stallions standing at attention, facing a fit, dark purple mare in a golden armor. She was walking back and forth as she gave the stallions what sounded like a rousing speech. Zephyr smiled at the sight and approaching confidently to take his place at the end of the line.

”Dismissed!” the mare shouted, ending her speech and sending the stallions trotting away just as Zephyr arrived.

”Nice speech!” Zephyr congratulated her, sitting down and clapping his hooves. ”Couldn’t have put it better myself!”

The mare glared at him. ”Who are you?”

”My name is Zephyr Breeze. The newest addition to the royal guard!” he said, offering his hoof to her. ”What’s your name?”

”On duty you may call me commander Tempest.” the mare said bluntly. ”Now, tell me why are you just now joining the sparring group?”

”Well...” Zephyr started, retracting his hoof unshaken. ”I figured since the train to Canterlot is always late I’d have time to sleep a little longer. Turns out it was on time though, so I had to catch the next one. But then there was so much time I-”

Tempest stopped him mid-sentence with a hoof to the lips. ”That’s enough.” She sighed deeply and shook her head, looking around the courtyard before continuing. ”I know this is your first day and all, but first and foremost a royal guard must be reliable. Understand?”

”Yes, absolutely!” he agreed. ”For the next lesson I will be there ten minutes early!”

She smiled. ”Good. Now, you can’t do the lessons out of order, but since it’s just you and me I guess I can give you a private lesson before the next session. Take off your armor.”

Zephyr blinked in disbelief as the mare started stripping in front of him, laying down her helmet and starting to undo the straps of her armor. He could only stammer in disbelief as he watched her armor slip off her back, sliding over her muscular body and slipping over her tight flank. Only when she was done and turned to face him bare naked did Zephyr snap out of his trance and start to hastily undo his own armor. ”Oh yes! Now that’s my kind of private session!” he exclaimed, his pulse rising from this surprising turn of events. As he finally managed to free himself from his armor and face Tempest again, he was surprised to find her glaring at him with her mouth open in disbelief.

”Is that your dick?!” she asked, pointing a hoof at his slowly expanding stallionhood.

”Er, yes? Don’t you like it?” Zephyr asked with confused concern, wiggling his hips to make it sway seductively.

”Get your mind off the gutter, this is a combat lesson!” she shouted, stomping her hoof angrily.

”B-but, you asked us to get naked!” Zephyr yelped, quickly closing his forelegs to cover his stallionhood.

”Yes, so we won’t scuff our ceremonial armor!” she retorted, pressing her hoof against her face and turning away from him. She took several deep breaths to regain her composure before addressing him again. ”It’s... fine. Just try to keep this professional, okay?”

”Yes ma’am!” Zephyr answered with a salute, his cheeks red with embarrassment.

”Good.” Tempest sighed. ”Now then, try to tackle me like they teach in your guard textbooks.”

Zephyr nodded trying to put his embarrassment behind him. Naked ponies were a common sight around Equestria, but watching her strip like that had made this a rather awkward situation. Nevertheless, he wanted to give it his best shot, backing away a few steps to give himself some runway. He dug his hooves to the ground and leaped at her with all his might, forelegs spread to catch her around the neck and push her on her back.

Everything went smoothly right up to the impact. He caught her between his forelegs and slammed his breast against hers, but instead of bowling her over like expected he felt like he’d hit a solid wall of muscle. Before he could catch his bearings, Tempest rolled him onto his back and stomped her rear hoof right between his rear legs. Zephyrs eyes bulged as her mighty hoof struck his balls, squishing them against his pelvis like they were made of rubber.

”AAGH!” Zephyr screamed, kicking his legs and trying to reach down to cup his aching nuts. Tempest smiled smugly, her strong forelegs preventing him from curling up as she let him squirm for a while before releasing him. He wasted no time rolling onto his side with his hooves between his legs to nurse his balls.

”You really need to work on your strength. But for now, let’s focus on technique...” Tempest calmly continued, idly walking a circle around the prone stallion before coming to face him again. ”Now stand up and try again.”

Zephyr was still gasping for air and holding his balls in agony. Tempest prodded him with a forehoof.

”I said stand up!” she repeated with mild annoyance. ”I’ll let you tackle me this time.”

Zephyr took a few more deep breaths before clambering up to his shaking feet, his balls throbbing painfully between his legs. ”O-ow... You stepped on my balls!”

”I know.” Tempest said with a grin. ”Now tackle me!” she commanded, standing still and looking at him expectantly. Zephyr gulped hesitantly, backing up and leaping at her once again. He slammed against her just like before, but with her cooperation he successfully ended up on top of her, pinning her down beneath him.

”I did it!" he gasped. ”Pretty good, right?” he added with a confident grin.

Tempest chuckled. ”Not quite. Who do you think has the upper hoof now?”

Before he could think of an answer, Tempest kicked her rear leg up, striking him right in his already aching balls. He screamed in pain as his legs buckled, landing on top of her with his battered balls still precariously close to her powerful legs.

”As you see, even though you are on top, your weak spots are completely exposed.” Tempest said, kneeing his balls for emphasis. Zephyr screamed in utter agony, each blow to his already aching testicles more painful than the last. ”In fact, as long as I have you there, you are entirely at my mercy!” she continued, wrapping her forelegs around him and pressing her knee firmly into his groin.

Zephyr screamed helplessly as her knee flattened his balls, grinding them back and forth against his pelvis. He struggled in vain against her powerful grip, his screams jumping in pitch each time her leg slid over his ballsack, his nuts slipping past her muscular hock with unbearable, gut-wrenching sensations. ”AAGH! My balls! Stop! Oh Celestia please stop!”

Confident that her lesson had sunk in, Tempest released her grip and let the stallion roll off her, landing next to her in a fetal position. ”Now, the purpose of this lesson...” she explained casually as she stood up ”...is to show that since the Equestrian military has always consisted of stallions, certain rules of combat have grown to be taken for granted. I’m not telling you to fight dirty, but you must be prepared for enemies that won't hesitate to do so.”

Zephyr couldn’t say anything, his entire body clenched up from the pain radiating from his bruised scrotum. He could barely hear what she was saying, but his aching balls were sure to keep the lesson in his mind for days to come.

”Any questions?” Tempest asked rhetorically, smiling with smug satisfaction at her hoofwork. Zephyr replied with just a pained groan, eliciting a slight chuckle from her. She bit her lip as she kept watching him with amusement, her ears swiveling in thought as she considered something. Finally, she lowered her head and used her forehoof to turn his face to hers. ”Actually, I have a question of my own.” she said in a sultry voice. ”Would you still like the kind of ’private lesson’ you seemed to be expecting?"

Zephyr stared at the powerful mare in disbelief. After the number she’d just done to his balls, this sudden chance of attitude had to be a trap. She didn’t wait for his reply though, instead simply tossing him on her back like he weighted nothing. He gasped as his swollen nuts smacked against the side of her flank, his mouth frozen in a silent whine as she started walking towards the barracks with his tender balls squirming against every movement of her muscles along the way.

Entering the barracks, Tempest closed the door behind her and tossed Zephyr onto the nearest empty bed.

”Oww... Thanks. I’ll be fine now thanks.” Zephyr managed to squeak out, trying to hush her away to protect his balls from any further harm. His panic grew as Tempest jumped up on the bed with him, easily pushing his legs apart and exposing his swollen pair, now nearly twice their original size.

”Mmm... looks like these boys learned their lesson.” she grinned.

”Eheheh, they sure did...” Zephyr responded with a forced smile, careful not to provoke her. His balls were in agony, and having the mare responsible for it breathing right down on them was setting off all kinds of alarm bells in his mind. He subtly tried to tug his legs free, but her strong hooves were holding him fast.

”Now then...” Tempest said, slowly releasing her hooves and walking up over him. Zephyr watched with baited breath as she lifted her rear hooves to his sides, one missing his balls by hairs width, the other just nicking the top of his right nut with a sharp jolt of pain. ”Let me see that cock of yours again.” she whispered, drawing his attention back to her face, now inches away from his and looking deep into his eyes with lustful gaze. ”You’re lucky you’re so cute.”

”Y-you think so?” he replied with an awkward smile. He’d have used the word ’handsome’ rather than ’cute’, but he knew better than to argue right now. He had a perfect view of just how strong the intimidating mare was, her slender feminine frame covered with big, bulging muscles. Behind her astonishingly well-defined rear legs he caught a glimpse of her tail twitching, before she aggressively pressed her lips against his in a firm kiss. Zephyr’s eyes widened in surprise - it looked like he was about to get some whether he wanted it or not.

”Oh yes...” Tempest cooed, breaking the kiss. ”I have a thing for girly stallions.” she continued, moving her hoof between his legs to rub his balls. Zephyr’s grimaced as she fondled his tender nuts, softly but still too hard for their current condition. He barely even noticed as his cock grew until it was flopping around at full mast as his hips squirmed to mitigate the pressure of her hoof playing with is balls. Tempest let out a pleased hum as she retracted her hoof, allowing Zephyr a moment to catch his breath before the touch of her wet marehood against his cock caught his attention.

Tempest reared up, pressing her pussy against his member and gasping in pleasure as it slipped inside her. Zephyr moaned in pleasure as his attention shifted away from his aching balls, enjoying the feeling of her wet pussy sliding down along his shaft. The feeling was almost enough to block out the throbbing pain between his legs until her muscular flank came to rest on top of his balls.

”Um, please be careful.” he asked gingerly, drawing air through clenched teeth as she readjusted her position on top of them.

”Fat chance.” Tempest said with a devious grin. She laid her forehooves on his chest and started to bounce lightly, rubbing her pussy up and down his cock as she started picking up speed. Zephyr gulped nervously, caressing her muscles while trying to find a rhythm that would minimize the impacts of her muscular plot against his testicles.

She moaned in ecstasy as she kept riding him, slamming her flank down harder and harder. Zephyr gripped her flank and started thrusting into her at full force, ignoring his bouncing balls as he approached his orgasm. With one more deep thrust his cock erupted inside her, her powerful legs clenching hard around him as she threw her head back in a scream of ecstasy. Zephyr groaned with pleasure, his genitals flooded with a mixture of pain and pleasure as they pumped their load inside her.

Tempest sat on him as they caught their breaths, his cock slowly softening inside her. ”Aah... That was great! I'd say you passed your first lesson with flying colors.” Tempest said with a satisfied smile, standing up and letting his member flop out. Zephyr twitched as it smacked him in the balls, snapping him out of his post-orgasmic haze and prompting him to cradle them again.

”Ow my balls...” Zephyr groaned, caressing them in an effort to soothe the throbbing agony. Sex with the strongest mare he’d ever seen was no doubt something to brag about, but right now he was in too much pain to say anything. Every beat of his heart made his balls feel like they were exploding.

Tempest chuckled, playfully ruffling his mane with a forehoof. ”Guess I really wore you out, didn’t I? Don’t worry, I’ll get someone to cover your shift today.” she said, hopping off the bed and heading for the door. ”Oh, and I’ll ask the maid to bring you some ice. Would you like that?"

Zephyr let out an approving groan, still cupping his throbbing groin as she closed the door behind her. His first lesson had been a short one, but his balls felt like he wasn't about to forget it anytime soon.

Author's Note

My entry for the LewdChapter's Muscle Mania contest. Turns out that for muscle worship an anthro story would have been much easier to write, but by then I was already halfway through the story. Enjoy!