Derpy pushed River against a wall. She felt his hot breath against her sweaty face, flushed and glowing.
"Derpy-" River started, his voice hushed. Wary. "We cannot do this."
"River, listen to me," Derpy said, as she moved her hooves down his lean, muscular arms. "I have a burning passion for you that only one thing can satisfy."
"Derpy, I cannot deny I have feelings for you, but I am in love with Twilight and-" Derpy hushed his loquacious mouth with a kiss of her own, brushing her tongue against his inner walls. He struggled for a minute, finally letting Derpy exercise her own control. She pushed her face against his muzzle fiercely, thrusting him further against the cold wall. River hugged the mare close, feeling her warm, shaking flesh. He pulled her close, savoring the sensation of another body pressed up against him. Derpy took this as encouragement, and rapidly increased the intensity of her kiss. They slowly shrunk down to the floor, and Derpy sat on his lap, her legs stretching out against the wall, pushing them together. River broke out of the kiss, catching his shaking breath. There was a fire in his veins, flowing throughout.
Derpy abruptly stood, and River quickly followed. Derpy distracted him with a playful kiss, their mouthes dancing together in the dim light. River shamelessly felt her body, appreciating her every curve and arch from a more intimate level. His arms fell to her flank, and he rubbed his hooves over it appreciatively.
Derpy smiled at him seductively, eyeing him in the heat of their own newfound rapport. He nipped at his lip and broke free, turning her back on him, and running to the other side of the room. A bed was conveniently placed there, its sheets silk and fresh in the Canterlot hotel room. She sprung into it with her usual exuberance, and rolled upwards, expecting the inevitable. She pulled off her sparkly grey dress, revealing her atypically sized breasts, glowing in the dim lamplight. River lingered foreword, suppressing a groan of anticipation, pulling off his vest we wore only for formal occasions and tossing it to the floor. Derpy squealed with delight as he crawled onto the bed, on top of her. They kissed again, gravity pushing River atop her warm, heaving body. Derpy's chest pushed against his bare skin, and a flush of exhilaration ran through River's body, accumulating in his loins.
Derpy's hands showed no hesitancy as she ran them over Rivers' chest, moving lower and deeper. "Oh," she said, giggling, as she discovered his new, throbbing member. She rolled him over, pressing him in another sultry kiss, suggestive and coquettish. She was on top of him now, and pulled her body downward, brushing her chest against his as she leaned to her goal. His horse penis, already fully erect, was roughly the size of two colts'. Derpy, despite having lusted over River with her wildest fantasies, was impressed.
Loosing no time, Derpy began to run her tongue over the tip, moving slowly downward after an elaborate slobber over his apex. She worked her mouth complexly, expressively, already having much experience on many, many muffins. His junk was far too large and thick to fully fit inside her demure maw, but she gagged and salivated over it as best she could, which was enough to make River shake and press his legs over Derpy's backside. Pushing, groaning. River was very liberal with his groans and sighs. Derpy pushed her head back and forth slowly yet deep-rooted at first, but than gained momentum and speed. As her head bobbed and lolled, Rivers' eyes reached the ceiling, a familiar light-headedness overpowering his pelvis. His voice was quivering uncontrollably as he murmured, "I'm gonna cum!"
Derpy loosened her mouth from his crotch and returned to a position on top of him. "I'm not done with you yet!" she sniggered, her face dripping with sweat, her eyes clouded with fervency. River groaned, tortured, mad with longing. "Please, Derpy," he whimpered, attempting futilely to propel his penis into some imaginary vagina. Derpy silenced his pleas with another kiss, slamming his face onto the bed's pillows.
Derpy, already having the pleasure of temporarily satisfying River, was feeling another longing inside her own mortal body. Her marehood already wet and dripping, smearing across Rivers' short fur. She wanted him so much, and eyed his leviathan penis lustily. This was her deepest desire (pun intended).
Standing on her knees, she made her way backwards onto the tip of his palpitating affiliate. They both nearly screamed with craving. Derpy, making sure to take her time and savor the moment to the best of her abilities, unhurriedly slid her way down his shaft. At first, it didn't fit all the way inside of her. Her soft scream, induced by the satisfying pressure of a thick, alive associate within her moist walls, stimulated River even more, and he pushed his flank back into the bed, preparing for the ultimate moment.
Derpy began to rock up and down. She glided upwards, and then felt herself clop down, the penis moving slightly deeper inside. She soughed alluringly, almost guttural, the fierce, raging animal section of her taking over. She rolled upwards again, and clopped down with more assertiveness. Rivers' penis was fully inside her, and she screamed to the heavens, "Oh, sweet muffins!" River began to fidget, rolling his thighs under Derpy's warm weight.
Derpy, in delightful pleasure, began sliding up and down more frequently. Sparing no dubiousness to yell and groan. River felt like he was immersed in a amorous inferno, his penis overpowering him with the familiar tingling, stretching cover, spreading throughout his entire body. With each clop, he felt his soul being drawn deeper, and deeper under, and if sinking into a giant spring. The feeling was simple incomparable, and the simple euphoria of the moment, the combustion in his genitals, was spiraling upwards, readying for the dramatic plunge.
Derpy was already ahead of him. "I'm cumming!" she shrieked. With one final, mighty thrust, Derpy's fluids emptied inside of him, rushing over, flowing throughout, soaking into his open skin, forcing an immediate reaction. With one final inhale, Rivers' penis exploded, firing fluid, enveloping the bawling mare on top of him. He yelled along side of her, creating some obscene symphony.
The pressure in Rivers' chest was released, and his mind and body felt empty, dry. But so content, so pleasured. He leaned backwards, pressing his hooves against his wet mane. Derpy removed herself from his shaft, and it flopped in the air, releasing its final outtake. Derpy flopped to his side, panting heavily. A smile spread on Derpy's face as she fell asleep on Rivers' chest.