When a man or woman proceeds to defecate and urinate in a jar for a number of days, to a number of weeks, then wait a month for it to ferment (remember to put some sort of lid over it). It is often stored in a hot humid area.
Once a month has gone by, get your boyfriend or girlfriend to lay in a bathtub and pour the excrement all over there body, then have sex with them.

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