The act of Inserting the index finger into a vagina for pleasure only to leave it there stationary until awkward silence is broken.
It is customary to salute these men when seen with the arm extended and the index finger pointed to the horizon.

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