Its a hot day, あなた and 200 other people are at the ビーチ and your in the water when suddenly your swim wear falls off and あなた become naked. What do あなた do?

I would work it

Matters the beach. Most likely just wait till dark then run to where I have my normal clothes and put the on.

Flaunt it. I'm proud of what I've got beneath the waistline!

Actually.... I try and get my 水着 back.... BUT I WOULDN'T BE AFRAID TO FLAUNT IT!

dive in to get it back

Probably shout it out.. Don't judge me😐

Become a mermaid and swim to the bottom of the ocean.

I'd sink down a bit, where the water reaches up to my chin. Lowering my eyelids, thinking "If あなた people come near me, あなた are asking for your deathwish" as I'm smiling :3

call your mom and say "mom have あなた seen my underwear??????"

Well, I would feel it falling off so I would dive and get it back. I'm a surfer so I can hold my breath for a long time. I wouldn't leave the water until I get it back. If I can't I'd shout out to whoever was there with me and ask them to bring my clothes.

...my コメント would be kinda inappropriate I think, so I'm going with this answer..
But um, somewhere in my mind it'll think everyone is happy now because their wish has been fulfilled.
Just walk around naked xD