to insert your penis on the zipper and zip up, causing massive devastation to your penis.
Dude, I was bored one night, and saw my zipper jacket on the floor. SO I decided to zipper fuck it. Not a very good idea beacuse now my dick looks like a pot-sticker.
When a couple is having sex in a sauna, both dressed in railroad conductor outfits, the woman doggy-style position, and the man doing her from behind. Then, right when the male partner is about to explode with jizz, he takes it out of the ass or vagina and points his penis up in the air and says "All Aboard!!" This is supposed to represent a steampipe from a train.
Last night Fred went to the local sauna with his wife and repeatedly steampiped her like a true train conductor.