Shaved testicles. Periphery's singer claims you can't regret this life-style transition.

"Once you go smooth sack, you never go back."

-Spencer Sotelo 2014.

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