Suggest that she might as well be his cum-dump

"They are a bunch of assholes," Karen said.

"Listen, Karen. Wendy got me all hard and didn't give me any relief. And you've got your tits out, practically hanging over me. Why don't you get down on your knees and let me fuck your mouth and cum on your tits?"

"What?"

"Come on, teenage girls are just cum-dumps, right. If you're not fucking half the school already, it's only because they're too cheap to pay your price. I know you want me. So, get down and suck me off. I need it."

She shoved him away and fumbled for her shirt's buttons, covering her tits with the still-open fabric. "Wow, here I was thinking that all the guys in the school were assholes except my brother. Who knew he was the biggest asshole?"

(Note: obviously this is a bad ending. I suggest you go to previous chapter and choose a different route)