So she was charging 1000 yen for each puff puff, and the Admiral gave 30000 yen.

I am just not sure, even after all those years, on what puff puff actually is... XD

It's a sexual gag joke that I recall was made by Akira Toriyama during the original Dragon Ball. Then it was brought back into the Dragon Quest series. Where it ties to imply the same thing, but usually concludes with hilarious results that doesn't imply what we think puff puff is in some cases.

Not knowing the original joke, I always assume it's a onomatopoeia of klaxon/air horn of which you squish the round part to make the "honking" (or Pafu-Pafu in JP) sound.

Totaku said:

It's a sexual gag joke that I recall was made by Akira Toriyama during the original Dragon Ball. Then it was brought back into the Dragon Quest series. Where it ties to imply the same thing, but usually concludes with hilarious results that doesn't imply what we think puff puff is in some cases.

To actually explain it.
Puff-Puff = rubbing breasts on head.
What puff-puff actually is = Rubbing two slimes on head.

Puff-puff is a skill related to the female character who's unique skill is "Sex Appeal." There are also NPCs who offer Puff-puff to the main character but tell them to close their eyes, which is where the gag comes from. there's actually a collection side quest in DQ XII to find all the bunny girls in the world and get a puff-puff service from them. and each one is unique.