When you're behind a lady engaged in safe sex, but it just isn't working. In one swift maneuver, you pull, grab, toss and pump - effectively removing the intercourse impediment from your Johnson.

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