A Big Johnny is when a girl is being gang-banged by two men; one penis in her mouth and the other in her vagina. If both men come simultaneously, she then pulls the penises out so that they ejaculate on each other's penises.
I was in a threesome once and we did a Big Johnny. My dick was sticky for three whole days.
An act where you terrorize multiple Jewish homes with that big dick hanging out while fucking the shit out of your uncle and selling children to pedos.
Girl 1: “My bff blew Chad the other night and apparently his dick was so big she had a hard time getting it all the way in there”
Girl 2: “ Wow, I wouldn’t have expected Chad to be a Johnny Big Cock”