With a make out session, of course

Without any further warning, Emily wrapped her arms around Lily's hips and pulled in to kiss her ass. Literally. She started with a smattering of kisses on each cheek, each one a little jolt of pleasure that Lily craved. Then Emily stared directly between the cheeks, her face flushed. "Mmm... babe, I know I've done this before, but that's before you... became so perfect. Before you were my girlfriend, instead of that girl you're attached to. Fuck I'm excited, let's do it!" Then she leaned in, shoving her face between the cheeks so she could kiss Lily's asshole directly.

Both discovered in the process something that had changed with the ass's increased size and perky shape: Lily's asshole was puffier now, a lovely little donut ring, almost like another set of lips. They fit perfectly against Emily's own, and Lily could hear the kissing that ensued.

She also felt it, her asshole's exterior was so fucking sensitive now. It was even better than when one of her partners would kiss the tip of her cock. She's... she's kissing my ass. Like, not doing so in the way you would to pleasure your partner, it's like she's kissing her girlfriend on the lips...

Of course, thanks to Lily's meddling with Emily's mind, that's exactly what was happening.

Eventually, after almost half a minute of solid kissing, Emily pulled back, breathing heavily. Of course, that ass was so big now, leaning in like that would make it hard for her to breathe. "B-babe, fuck, this is so hot. I've never gotten this turned on from kissing someone before." Then she looked up at Lily, wincing in apology as she asked, "Uh, roomie, I hope it's okay that I've kind of pinning you like this. I just need a little time with my new girlfriend, then you and her can go about your business as usual, promise."

"O-oh, um, sure." The feelings of hurt from being talked to as just a roommate, the way Emily talked to Lily before they started dating, were vastly overwhelmed by the kinky joy in seeing her talk about Lily's ass like she was her own person.

"Thanks! I'll make it up to you." Then, turning her full attention back to the ass, Emily purred, "This time, let's use some tongue," before diving back in. She'd meant it, too. After only a few kisses like the ones she'd done before, she slipped her tongue inside, and Lily couldn't stop herself from moaning, her hips jerking. That didn't stop Emily, of course, she moved with the hips, staying lip locked with her new ass of a girlfriend.

The inside of her ass must have changed too, the few times a partner had tried eating her out before, they'd said it was too tight. Now the tongue slipped in easily, and it felt so absolutely fantastic too.

It only took about ten seconds of tonguing before Lily couldn't help herself, couldn't hold back any longer, and her little cock twitched, a small load of watery cum dribbling out from the tip and falling to the bedroom's carpet floor. It was hard to remain standing, but she did. "O-oh fuck, Emily, that was... that was good. You can stop now."