The sound you make when bopping a helium-filled foil balloon that is tethered to a weight. You hit it and say "doink" and watch it rise back to the top so you can doink it again.
Sam is flicking his finger at a foil balloon.
Sam: Doink.
A word to be used contextually in almost any situation and interchangeably with almost any word, often in a positive context.
1. Yo this doink goes stupid hard
2. Hit her with that doink bro
3. That doink was so crazy
Im in amish smoking some big fat doinks
Me and daniel went out for a doink