a cross between a can and a bottle.

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

cottle-cunt in a bottle

Imagine "bottles" your baby.
Now the b turns into a "c" as "c" = cock.