Revealing mistake: When Julia does her dance for the firemen, they hit her with the fire hose and she gets knocked back. In a few shots after that, especially in the close-up of her swishing her hair back, you can see on her neck that the neck-fat piece has come loose.
Revealing mistake: When Andy is talking to Grant and has just met Julia, they go to sit down and she takes her whole bikini off. But as she sits down you can make out the strap of a flesh-coloured thong, even though she is supposed to be fully naked.
Revealing mistake: Near the end of the movie when Andy is falling down the stairs you can see the padding under her shirt.
Answer: The song is Crump Clown by Rize.