"Talking in Your Sleep" by the Romantics

I came up with this one years ago, when the video was in heavy rotation on MTV.

Original lyrics:
I hear the secrets that you keep
When you're talking in your sleep
I hear the secrets that you keep
When you're talking in your sleep

Lewd lyrics:
I hear the secrets that you keep
When you're fucking with your sheep
I hear the secrets that you keep
When you're fucking with your sheep

The funniest thing about these lewd lyrics is the idea that a sheep-fucker would engage in pillow talk after doing the deed. Then again, they are the Romantics!