I know we give our pets a lot of human qualities in our minds, but folks, only a human would pee on someone's bed because they were "mad"! (ewwwww, what am I THINKING!! yuck!!

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I bet Baby was so involved in watching you get ready to go and not wanting to leave your side that she held it just a little too long. And you were so involved in getting ready, you probably didn't pick up the "Mommy I have to go wee-wee" signs!
So Baby jumped onto the bed where she knew you would be able to KNOW she had to pee, and then just could NOT hold it any longer!! Bad Momma, not letting Baby pee in her rightful place because she wanted to be near you!!! Bad Momma!!