Critically important

Why do you think they call it a "blow" hole?

Dolphins would have a pufferfish take the coke, then eat the pufferfish. It's very efficient.

Bit difficult underwater, that cocaine is going to float everywhere and dissolve.

That dolphin-cocaine size ratio tho. Enough to get everyone in Bikini Bottom high

I'd say there's at least a 90% chance that this was addressed in some background gag in Bojack Horseman lol

Both not practicable (no arms, cannot move upside down) so the dolphin needs a human "friend" to blow it into him.

yes, like this

That sounds like something that dolphins would do

Yes.