titty swamp

Titty swamp is when your boob sweat is accumulated under the said boob or boobs (or bra) and creates a layer of film that coats the skin.

Or in other words
Female duck butter

Sydney: hey Lizzie, on a scale of 1-10 how bad do you get titty swamp?

Lizzie: I'd say a 6. It get so bad that skin starts accumulating under the finger-
Sydney: what the fuck is wrong with you?

-scene-