Haha me and my friend were actually just talking about this the other day when we were listening to PCD - Stickwitu and she sang 'making love at the sea' instead of 'making love endlessly' lolll.
I also thought they sang boobies in When I Grow Up haha. I think that's a common one though.
Also I have a friend who for years thought the 'You're Gorgeousssss' part in the Baby Bird song was 'Slow coachesssss.' Lol.
Others:
I Think We're Alone Now - Girls Aloud
Misheard: There doesn't seem to be any water around.
Actual: There doesn't seem to be anyone around.
Rude Boy - Rihanna
Misheard: Call me rude boy
Actual: Come here rude boy
Don't Talk About This Love - Cheryl Cole
Misheard: Like I could drown, it's syphilis.

Actual: Like I could drown, it's effortless.