"Ay. Ay ay ay ay. Ay. Nobody's going nowhere." You approach the massive booty, with a girl attached. She seems really small by comparison to her huge ass. You place your right hand on her chin, guiding her mouth to yours and your left smacks her ass. Cassie's core tightens as she kisses you for several seconds, before pulling back.
"Really?" After several minutes of watching her, Cassie's glare now seems more like an angry kitten. "You promise?"
"I won't leave until you can walk out of her on your own. That's a promise." Another quick kiss as your rub her butt, leaving her smiling as she hugs you. "Let's get you back on your feet again."
First problems first, her orgasms are making her seize up, so even if she did have the muscle she couldn't. You could stop the sensitivity, buuuuuuut where's the fun.
"Orgasming won't inconvenience you anymore. You can talk and move normally while orgasming." She stops shaking a little bit, but she's still crying. Cassie seems to have a loooot of stuff bottled up. Next up, the "standing up" issue.
"Your legs, no your whole body is strong enough to move without inconvenience." Now she can also pull herself up with her arms, at least so you thought. Doughy thighs tense as muscles develop underneath. Arms bulk up, and her hug nearly crushes you for a moment before she adjusts.
"I'm sorry, that was my fault..." She's no longer constantly moaning, but back to her quiet glaring self. You think she looks sad, but she's too busy making sure you're not hurt. She stands up, sending those cheeks a jiggling again. You can now see the muscles throughout her body, covered by a thick layer of bouncy fat around her butt, then tapering the further down you go.
Because of the whole "no body hair", her pussy is clean and puffy. Her thighs rub constantly, lubricated by her own juices. You can see her butt from the front, and her small perky tits under her running jacket that's managed to survive all her transformations so far.
"Are you alright? I didn't mean to hurt you, I'm sorry..." She looks somewhere between about to strangle you and about to breakdown crying. A strange look with no middle ground.
You brush her off, making her smile slightly. She brushed some of her short blonde hair from her eyes. "Are you going to keep changing me? I kind of... like? Being big now? Oh, but I'd be delighted you took me. Hugged me and stuffed this fat ass... Kissing and snuggling..."
Her hips twist as she indulges herself in fantasy, eyes closed. You decide to...