1.When you and your friends are sitting around and one of you makes a joke and every one starts laughing hysterically.

2.Just another way to say "laugh real hard" but in a more silly,sexual manner...hence, the 'jizz' in gigglejizz.

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