When a drunk girl explosively shits herself in and around your home and you proceed to rinse her off in your roommate's shower. In doing so, you become turned on and join the soiled girl in the poo-stained shower and proudly have sex with her.
noun
1. Informal
a. The art of hiding your genitals in otherwise normal pictures (or video) so that the victims do not notice you have shown them your genitals until it is too late if they notice at all.
b. Photobombing...but with your dick.