The Island
"Come now, I don't want to push you any further and narrow your chances of winning, do I?"
"Right. So no more stroking for you. Instead, you can put your throbbing cock in between my breasts and massage them for me."
"Oh and don't think if your little task makes you cum, you can pretend it never happened. I'll just tell my mistresses you were jacking off to me on the beach whilst I was swimming."
"Come on then, my breasts need a cock massage", she says teasingly.
You place your cock in between her breasts and she pushes them together, smothering your cock.
[Put your cock between the back of your hands and stroke your penis like that until you edge. Lube or wet your hands if you want.]
She begins to bounce in the water, her breasts rubbing against your cock mercilessly.