Okay, this is one from my teenage years. I was on a holiday with a group of friends. It was hot, it was sunny, so we spent a lot of time at the hotel pool.

As did, unsurprisingly, many of the other hotel guests. The adults mainly sunbathed on the loungers on the poolside but the pool was generally filled with kids of all ages. As late teens, we were some of the oldest in there, but we made ourselves popular with lots of parents by playing with the younger ones and keeping them occupied. We didn't all speak the same language, but that didn't stop us horsing around and having water fights together.
A few of the younger teen and pre-teen boys and girls would occasionally try to pants other boys of their swim shorts while they were in the pool. Pointing and wiggling a finger at a boy who's just been depantsed is universal and needs no words or translation.

My friends and I mostly stayed out of such antics, leaving that type of game to the younger ones. Partly because we didn't want to become victims ourselves, especially the girls but also us boys. I'd always make sure my own swim shorts were securely tied.
But then, towards the end of the week, one of the more boisterous kids, who would've been about 12 or 13 and was the unofficial leader of a big group of them, was prancing around on the poolside, showing off and throwing things to the kids in the pool. He wore baggy Bermuda shorts that hung low on his skinny, almost non-existant hips. Most of my group of friends were in the pool at the time, but I was out on the poolside as well and about to jump in. I was some distance back from the pool, behind this kid. He hadn't noticed I was there. I realised it would be so easy to grab the sides of those baggy shorts and yank them down. Then he wouldn't just be showing off to the other kids, he'd be showing
EVERYTHING to the other kids.
I crept up silently. He remained unaware of my presence, although some of his audience saw me sneaking up. My hands reached out toward him...
I shoved him square in the back. He cartwheeled his arms madly for a second in an almost cartoonish way, trying to keep his balance, before toppling forward and splashing loudly and ungracefully, face-first into the pool. Everyone laughed. Several kids swam forward to grab him and dunk him under again when he surfaced. He wasn't hurt, other than his pride. He spluttered and looked around to see me grinning on the side, and grinned back at me, as if to say, "Fair play!"
Probably, I made the right choice. If I'd
ACTUALLY stripped him naked in front of everyone and his parents saw, or if he got upset and ran to tell them, I could've been in big trouble. So I settled for making him suffer a lesser indignity instead. It was still funny, just not
AS funny. He spoke English, and I kind of wish I'd told him just how close he'd come to showing off his pubescent boy parts to everyone, to see how he reacted.

But I didn't.