"I know!" she says with that same pouty look on her face. "I need you to edge!"
[edge]
"Okay, hold on, hold on now," she warns you, as you are panting, close to orgasm. "It should go without saying, but don't you *dare* cum!" she demands.
You mumble acceptance.
"Hmmm," she says after a moment of studying your lube-slickened cock. "Get box number five," she tells you next. You retrieve it, and pull out a thin, white cord. "I bet you know what that is for, right?"
[answer her!]
"Exactly! Tie up your cock and balls. Make it nice and snug around the balls, that's important!" she tells you.
[tie up your cock and balls with a cord or something similar]