The penis.
Called a sex gun because that is what a guy shoots semen into a woman's pussy ect. with.

when a n*gga fuck you with his glock in yo mouth type shit

n. (Seh-ehcks deet-ehcktohr guhnn) 1. Used by the Jesus Patrol to find traces of sex, in spots wear Jesus most recently had or used sex.

when a n*gga fuck you with his glock in yo mouth type shit

Gun Sex, Is when you shoot someone. The bullet acts as a sperm, and if it enters something, Then it is gun sex.

Machine gun sex is characterized by violent, rapid, repeated thrusts.

Nerf gun sex is were you invert your penis into a nerf gun