1. Someone who goes round ripping people trousers and underwear off, then they usually just take your penis.
2. An alternative to calling someone homosexual or gay. It literally means they jack off to penis, therefore called a penisjacker.
1. Guy 1: Hey, what happened to your clothes?
Guy 2: A goddamn penisjacker was in the bushes, he jacked my penis.
2. Guy 1: Ralf, what's johnno doing in the closet?
Guy 2: Leave him, he's a penisjacker - jacking off to nobs.