Hang her upside-down

"For instance," you suggest, "what I could actually do is hang you upside-down from this palm tree."

"Don't do that."

"No, I think I will." You loop the line over the top of the nearby tree and tug on it so the buxom blonde is hoisted into the air, swaying back and forth in the gentle sea breeze. She has to grab hold of the front of her bikini bottoms with two hands to keep gravity from pulling her right out of it. Even so, the swimsuit slides up her hips, baring her pert little bubble butt and threatening to expose her pussy if she lets go for even an instant. She hangs in the air, a blush burning in her cheeks, desperately trying to find a way out of the situation as curious beachgoers gather round to watch.

"Hey, now people are definitely looking at your butt."

"Yes! I know that! Do you think you could maybe cut me down from here?"

"But you can get down at any time. All you have to do is let go of your bikini."

"I..." The blonde spins in slow circles, visibly frustrated as you and a bunch of interested young men in swim shorts scope out her cute behind. "I can't do that!"

"Why not?"

"Because my... you know why! Don't pretend you don't!"

"Because your bottoms would come off?"

"Can you please just cut the line? You're embarrassing me!"

"Pretty sure you're embarrassing yourself. Hanging there with your butt out when you could just get free at any time. Cute butt, though."

The blonde bites her lip. You can tell she's feeling very exposed in the posterior area, but she doesn't like the idea of streaking back to the changing rooms with nothing on below the waist. You tug on the line a bit, hoping to speed up the decision. She squeaks as the bottoms almost slip out of her hands.

"You could just hang here all day, I guess."

"I... you're mean! You're a mean person!"

"Look, I'm not the one who walks into other people's fishing lines."

The blonde gazes longingly down at the soft sand below her. So tempting. So easy to drop into. You can tell she's about to go for it. You take a hold of the line, waiting for your moment. Just as she lets go of the bikini bottoms you give it a firm jerk, yanking the swimsuit up into the air in exactly the right way.

She falls. But not very far. Instead of liberating herself from the bottoms, she's gotten them tangled around her ankles. Which means she's now hanging in the air, about an arm's-length from the ground, by her tangled bikini, bottomless in front of everyone.

She squeals, her face burning red. Her long golden hair lashes around as she kicks and sways, trying to wriggle free of the bikini. It's no use. She's stuck fast. One hand flies in between her legs, doing its best to conceal her pretty pink pussy, while the other tries and fails to cover her bottom.

"Hey! You cheated! That's not fair!"

"Well, you should look where you're going. What do you expect? Obviously if you don't look out for fishing lines, you're going to lose your bikini and end up showing your pussy to the whole beach. That's just basic common sense."

"Listen, this isn't funny any more!"

"It definitely is. See, everyone's laughing."

"I'm not laughing!"

"So you're saying I should tickle you?"

"No! Just let me down!"

Thoughtfully, you consider the spectacle of a very embarrassed buxom blonde hanging upside-down from a fishing line with her bikini bottoms around her ankles. A little charm ensures that she won't suffer any ill effects from being upside-down, meaning you can leave her there all day if you want. Maybe you should tickle her, or take off her top. The possibilities are endless.

"Everyone has to stop looking right now! I mean it! You're not allowed to look! When I get down, you're all in so much trouble!"