You know when you're getting older because when you take a bath, your balls will float!
Acid on your skin in never a good thing.
You wouldn't use vinegar on your face, so why your genitalia
I doubt anything detrimental will happen since vinegar is a weak acid, but I also doubt it will shrink your scrotum. If you don't want them to hang there's a procedure you can have done that's similar to a tummy tuck but on your scrotum.
Did you hear how long it would tighten up for? could be because vinegar is cold lol
Why cant you just stand in a really cold room butt naked?
I have never heard of this being done seriously, only mentioned in jest.