drop a bean 

taking a quick and tiny pellet-like shit

or

in sexual intercourse, failing to pull out in the nick of time - therefore leaving a bean-sized amount of jiz in the vajayjay

"Dude you weren't in the bathroom long at all"

"Yeah, I only had to drop a bean."

or

"Omg, I'm so scared I might be pregnant!"

"Wait, I thought he pulled out?"

"Ugh, he did. But he totally dropped a bean."

drop a bean by Katrina da fynest February 27, 2010