In order to extinguish the flames at Ox-King's home on Fire Mountain, Bulma, Goku and Oolong ask for Master Roshi's help. The dirty old man agrees in exchange of peeking at Bulma's tits.
Once the flames are extinguished, it's time to fulfill the agreement.
However, Bulma plays a trick to the old man and asks Oolong to trasform into her, taking her place in honouring the promise.
Reluctantly, Oolong turns into the girl's appearance and exposes the bosoms to Master Roshi (going even further with the "puff puff" affair, as the series fans already knows).
Based on "Dragon Ball" manga/anime show.
Line art and coloured version included.