"Keep the mouse in the house". It's a saying that can make anyone laugh if referring to the embarrassing situation when you just can't help but notice that a guy's weiner is in full view when he's sitting inappropriately with his legs spread. Or when it's peeking out of his boxer shorts. You try to cover your eyes but you just HAVE to look. Well, I can say for sure that this little saying ONLY applies to penises. And I can say that because I have a mouse in my house and I would prefer to not keep him here.