Swim suit trouble.?

I have rather large for my frame, and always have a problem of almost falling out of my bikini top during the summer. I don't want to sacrifice my cute bikinis because my s are annoying. is there maybe like a water proof adhesive tape or something? similar to what many people use in strapless dresses of shirts that are low cut and loose? a double sided tape? I just want to keep them in the top!!!!!