A slang term used to describe women who've had an excessively high number of sex partners / high body count that makes reference to the quills on a porcupine.
"If she had as many dicks sticking out of her as she's had stuck in her she would look like a porcupenis".
"That porcupenis is for the streets".
"Stay away from that group over there, they're all pocupenis's".
"Stay away from that one, she's a porcupenis