Christina Aguilera needs to read a guide on 'What Not To Do When You're Wasted' because she broke a cardinal rule... Don't pass out in the bed of someone you don't know. According to Us magazine, the drunk ho couldn't handle her liquor and apparently thought it was a good idea to take a little drunk nap in Jeremy Renner's bed when she attended his 40th birthday bash on January 8.

"Someone comes and tells me she's in my room. I run up and open the door and I'm like, 'Um, hi. What are you doing?' She just starts slurring. Her boyfriend [Matthew Rutler] was rubbing her back. Who comes to someone's birthday party that they don't know and gets in their bed?! My parents were there!"

What an idiot! Another source added "Christina was a mess at that party. She acted like a fool. Her boyfriend was shushing her and telling her to go to sleep."

Oh great. She's one of those chicks who gets trashed and becomes completely annoying. It's obvious she's dating a dude who doesn't know how to keep her from making an @ss out of herself. First the cat fight with Julianne Hough and now this? Christina's turning into a dirrrty girl. Step aside Britney, we've got a new hot mess in town.