An awkward, clueless dork possessing no mojo or confidence with the ladies. The kind of guy who'll get hopelessly tangled up trying to undo a bra strap (should he ever fluke getting that close), or get his dick caught in his zipper at the key moment.

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