Invite her on your lap

"Why don't I just fuck you now? I can't wait," you tell her as you slide her over onto your lap.

Smiling, Bianca grabs lubrication from her purse and strokes your cock with it, then climbs up, sliding your cock deep into her asshole with her dick pointing to the sky.

"Fuuuuuck, that's what I needed. God, fuck me deep, Matt."

You look around, in no immediate danger of getting caught in the back of the room.