May of made a mess of posting this. Thanks Joe, if you have to tidy up.
The thread on improper language brought this to mind. There are many songs in which rhymning patterns etc are used to create anticipation of vulgarities, which are either averted at the last moment or at least resolve innocently. For instance:

Oh she's got a lovely country residence (twice)
She's got a lovely cunt
Got a lovely cunt
Got a lovely country residence.

Children, needless to say, think they're hilarious. Have such songs ever been collected together? I don't know if the genre is sufficiently recognised to have a name, but I thnk I've heard a couple of them called "teasing" songs. Anyone know good examples?