The pounce happens when you see a stripper on stage and her thong slips as shes bending over to do a sexy little move. You already have a boner, so you whip it out and run on stage and stick it in her while she's unexpected. She yells at you and her bouncer kicks you out of the club. But just remember, you had it in their for a while, and you know she liked it.
Dude, some guy used the pounce and ended up in jail on criminal charges.