Cutie Mark Crusaders, Spell Testers!

“Me next, me next!” Apple Bloom jumped in place with glee. Seeing the half-lidded expression on Scootaloo's face, she knew she was in for something fun.

Twilight had a glint in her eye, happy to see the enthusiasm come back out. “Alright my eager little helper, hooves up just like Scoots did.”

The process began much like before, with two bumps slowly expanding beneath Apple Bloom's teats. Her breasts were slightly larger than Scootaloo's, the Apple family being notoriously endowed. Twilight wondered how that would affect the spell. As the balls quickly plopped out into the sack, they stretched the skin tight as they grew slightly faster than the flesh around them. Apple Bloom winced, and Twilight quickly made efforts to speed up the growth of the sack. "Sorry. I'm still getting the hang of this." She took some more notes, immediately taking notice of the size disparity between Apple Bloom's testicles versus Scootaloo's and her own. Her attention divided, the pair of balls continued growing unchecked, pulsing with purple energy from within. By the time she looked back they'd grown to the size of grapefruits. Apple Bloom's scrotum now hung low, dangling nearly to her knees, and its fur never thinned, instead leaving it covered in the same fluffy coat as the rest of her.

Apple Bloom rocked her hips side to side excitedly, feeling her pendulous sack slap back and forth between her thighs with a dull plap each time. Twilight's eyes got wide, and her magic flickered as her concentration was broken. "I-, um... think that's enough of that." Twilight said, reaching out a hoof to examine her handiwork. She lifted the weighty, egg-shaped orbs, and traced along the prominent vein that adorned each one. "Let's see what else you have in store."

Twilight made short work of forming the sheath, stretching it outward from the center like she was sculpting a vase. Its color, she noted, was split between brown and tan, and much to her surprise the width settled to about the same as Apple Bloom's hoof. The floating magical essence once again went inside the sheath, but rather than disappear it stayed perfectly visible in the gaping hole. This time for the cock she decided to work on the details as they came out, rather than apply them once a featureless tube had formed. First came the flare, which immediately started to stretch out the sheath as it formed. Its broad, spade shaped top quickly took shape, and details like the urethra and nubbed edges quickly followed. It wasn't long before it exited from its confines with a wet pop. As it did, a bead of precum was flung onto the floor, with another string waiting to fall from the tip.

"Oh, do be careful not to drip on the floor too much, Spike'll have to mop all that up. Actually..." Twilight's voice trailed off, and she cut off her magic and ran to her kitchenette. She soon returned with a large glass bowl, which she placed on the floor beneath Apple Bloom after wiping up the small splatters of clear, slimy fluid. Once she was sure there'd be no more mess, she continued, extruding out the shaft. Each time she grabbed it by the base and slowly stroked downward, another quarter inch appeared, and much to her surprise, another dribble of precum came out. Apple Bloom moaned in subdued bliss each time. It took until inch six to reach the medial ring, which once completed formed a sizable ridge as wide as a fully engorged flare.

"Wow, that's where you put the ring?" Sweetie Belle cried out in amazement. This was far different looking than what she'd seen in her schoolbooks. She never imagined they could be so big.

Twilight nodded, but seemed confused. "Yeah, I can feel there's a lot more left."

Apple Bloom's fat maredick continued to snake out of its sheath, bit by bit, dangling freely between her legs. Its coloration was mottled brown and tan, with large splotches of the lighter hue covering the top third, a patch on the side, and little speckles around the rest like splattered paint. By the time it was done, it was nearly touching the surface of the collected precum in the bowl. That is to say it was nearly as long as her legs, and considering she stood at just under 3 feet, that meant it settled in at around 14 inches. "Sweet Celestia. Looks like you take after your brother." Twilight commented.

"Apple must not fall too far from the tree!" Scootaloo shouted, always the jokester of the bunch. She and Sweetie Belle stood back watching in awe as inch after inch of thick piebald flesh emerged from their friend. Apple Bloom blushed and covered her face with a hoof, secretly enjoying all the attention. In all honesty she'd always been amazed and a little jealous of Big Mac. That fact, combined with her gifted lineage, Twilight's expectations of what it would look like, and Twilight's arousal from Scootaloo's musk subconsciously influencing her magic all added up to a cock fit to rival his, even at her diminutive size. She flexed it with pride, flinging yet more pre onto Twilight's nose, which she casually licked off without saying a word.

"I think that's about enough for you little missy. Go on over and stand with Scootaloo." Twilight said as she retrieved the half-full bowl and set it on the table with the vial of Scootaloo's cum. "And ah, this sample should be more than enough, but if you'd care to... finish, that'd be helpful. Just try to keep it tidy." As she spoke she looked into the kitchen and levitated another slightly smaller bowl to the main room for the job. She hoped it'd be big enough, or she'd have to do a lot of cleaning or a lot of explaining.

Apple Bloom returned to her place by the door and started trying to get her hefty member hard. The sheer weight of it made that pretty difficult, but Scootaloo was happy to help. She laid down on the floor underneath and started to play with the cock with her hind hooves. She batted it around awkwardly for a while but it soon stiffened up enough to grip and stroke. It swung upward and back down rhythmically as it reached full mast, gaining a couple inches, and dripped a line of its warm precum down the middle of her body. Not just her belly and chest, she realized - it also painted down her own hard horsecock, adding to the already shining sheen it seemed to permanently have. She reached a front hoof down to stroke it. Her mouth opened as she felt her breath quickening.

Apple Bloom's cock now drooped down in her face, and the flare swelled intimidatingly as a drop of pre fell on her tongue. "H-hey, watch it!" She said teasingly through laughter. Now that it was hard, Scootaloo could easily push Apple Bloom's dick up against her belly, where it proved long enough to nearly pass her chest. With a little stretching, Apple Bloom could simply look down and lick the head to prevent any more leakage, savoring the salty juices. Meanwhile Scootaloo humped upwards, grinding her lubed up dick against the one twice its size above her.

Twilight smiled at the pair as she watched them enthusiastically enjoy themselves, but her mindless voyeurism was interrupted by seeing a hint of white in her peripheral vision. "Oh! I'm so sorry Sweetie, I didn't forget about you. Step on up!"