Ty looked over at the small animal cage sitting next to his computer on his desk and got a twisted idea. He opened the door of the cage and took out his pet mouse, Cheddar, who had been watching the events with curiosity and excitement through the bars of the cage. He set the virile male mouse next to June and watched. The mouse quickly went to work, lapping at the juices dripping down her legs, starting with her ankles and working its way up her calves, then thighs. June moaned in agony as the mouse started quickly lapping at her sopping pussy, desperate for release. Cheddar’s tiny red prick became visible through his soft fur as he began thrusting at her snatch but unable to hit home. June started thrusting back against the mouse, struggling against the elastics that bound her. Frustrated, Cheddar stopped thrusting and chewed away at the elastics binding her tiny legs. June spread her legs for the mouse in response, presenting herself to Cheddar in doggy style, immediately ready for penetration. Cheddar lunged, gripping her sides with his tiny paws, then plunged his tiny mouse dick into her wet pussy and began thrusting rapidly. June began moving in tune with Cheddar, her juices coating his fur slick as he fucked her. Her tiny breasts swung below her as she was mated by the small animal. The mouse pulled her in closer and started pounding the tiny woman, his huge balls slapping against her passage as she screamed and clamped his dick with her vagina, pumping his shaft for release. That’s when the mouse squeaked, then thrust as deep as he possibly could, and spasmed, filling her womb with his fertile seed. Ty then decided that June was ready for release, and she began having the biggest orgasm of her life as Cheddar pumped her full for several minutes as June experienced multiple orgasms. Exhausted, the mouse dismounted for a moment and began licking himself clean as June lay still, basking in the glory of her last orgasm in a puddle of their juices. Before she could think twice, the mouse was upon her again. Cheddar grabbed her tiny waist and started poking for his target as June struggled. After a few tiny thrusts, Cheddar was back in her pussy. June gasped, orgasming again and cumming around Cheddar’s dick, not ready for a second round, but enjoying it nonetheless. This time, something new started happening to June. 6 tiny pink nubs formed below her jiggling breasts as new nipples formed in a row with the final pair just above her crotch. June moaned and gasped as they started to swell, buds forming as they grew into new breasts until she had 8 breasts bouncing together below her as she was ducked by the mouse. She felt her spine tugging as a pink tail formed, snaking out between her legs. Cheddar gently but her neck to hold on as he thrusted deeper into June, she pounded her ass back against him to help his tiny member go as deep as possible, his whiskers tickling her neck. Her skin grew itchy as white fur began to coat her body. Her ears began getting larger, now able to pick up on the tiny hypersonic squeaks Cheddar made as he kept pounding as hard as he could. Her body began to change shape, gaining some weight, and Cheddar grabbed on tighter against June’s now squishy sides with his little paws. Her moans began to change in pitch until her voice was nothing but squeaks, her face changing into a tiny muzzle with whiskers. Her small vagina tightened even more around Cheddar’s prick, now starting to match his anatomy. Lastly, her tiny hands changed to even smaller pink paws. As her changes finished, Cheddar started pumping faster and faster until he was deep in her womb, then came hard inside her new mouse vagina, filling her with his giant mouse testicles and they both squeaked in unison, orgasming again, June’s head thrown back in bliss as Cheddar bit down gently on her neck and squeezed her sides with his paws, making sure his seed fertilized her as he kept pumping her full. If he was lucky, she’d have a litter of up to 20 little baby mice squirming inside her soon. They both lay on Ty’s desk for a few moments, exhausted. This time, before dismounting, June felt a thick, each substance enter her. Cheddar was sure to seal her pregnancy as he planted his sperm plug inside her so no seed would escape this time. When he hopped off her back, she still lay exhausted and panting. Cheddar ran around to her front and began lapping her face and mouth, then started grooming her from head to tail. He pushed her gently, then delicately ran his quick little tongue across her new mouse teats, moving his way down. Finally, he cleaned around her crotch, licking the outside of her vagina clean. After receiving her bath, June got up and started grooming her new mate back. She finally felt satisfied, but grew concerned as she sobered up and considered her new situation, feeling the excessive amount of mouse spunk stretching her womb taught.