Grind against him

You reposition your legs into a straddle and start grinding against his groin.

"Two can play at that game." you say.

He grinds into you as well, after a few minutes you feel a hardness start to press against your clothed pussy. Breathing heavy and panting, you say

"Looks like, ah, I might win this, ahh, after all."

"I wouldn't count on it!" he yells as he slides both his hands into your panties from behind and he starts groping and pulling your butt cheeks, grinding you harder into him.

"Ohmygod, Dean!"

"yes Lily?"

"oooh goddd... ahhh. MMMMM."

"You are gonna have to try harder than that to beat me."