Having anal sex for the first time. Also could refer to losing/popping the "ass cherry". Normally used by a guy when talking about having sex with an anal virgin
Other versions include:
Popped the trunk, Popping her trunk, Popping his trunk, Popped my trunk
Guy 1-"Hey dude, you gotten your girl to give up her cherry yet?"
Guy 2-"No, but tonight I'm going to be Popping the trunk."
When you giving it in the pooper to a first timer, at first you need to get in slow and then pull out really fast, causing a popping noise and the overflowing of god knows what.
Bob literally shit and squealed like a bitch when he found out Sutter was popping the cork.
Joe decided it was time to find some freaky people and popping the clutch with men or women would be a good night on the town. he met a man named Jake at a birthday party and got a piece of that ass all night long.