The act of taking a dump on a moldy tuna fish sandwich, putting it in a blender, adding the fecal matter of a 12 year old cat, and throwing up in it as you scrape it off onto a bright blue tarp. You than take the gooey substance and have you and a group of your 7 closest freinds do a circle jerk into it (you must have an 8 way climax). Cuff a long drawn out fart onto the disgusting mass, squeege a weeks worth of ball sweat and an M-80 into a rotten sock and smack an unsuspecting woman in the face, letting it explode on impact.

A jack off buddy (from 'cum' /'come', meaning 'semen', and 'companion'); a friend that you get together with for sessions of solo or mutual masturbation
Variant of: cumpanion (from 'companion' & 'cum'); jack off buddy & wank bud & JO buddy
Similar to: fuck buddy