A form of emo sex. When two people who's bodies are covered in piercings love each other very much, they porcupine-fuck. porcupine-fucking normally leads to long stays in the hospital and/or skin replacement.
It can also mean when two people who have dried up herpes fuck.
DUDE! That porcupine-fuck we did last night made my dick peel for a whole fucking WEEK!
Porcupine-fucking is like dying my pussy red!