to ejaculate so much that you need a whole box of tissues to clean up
Guy 1: ACHOOOO!!!!! u got any tissues?
Guy 2: naw man, earlier i had a tissue box orgasm
when you think you're going to get caught masturbating so you ejaculate as soon as possible and grab the tissues rapidly causing many tissues to come out as well
Guy 1: Dude my mom almost caught me rubbin it out!
Guy 2: That happened to me too, I had a tissue box orgasm, but my mom didnt even come in my room... FUCK