Photo via Splash

It didn't surprise us in the least to hear that Britney Spears drunk-dialed Kevin Federline on her 26th birthday celebration night out. Given her behavior of late, in fact, the drunken dialies are kind of endearingly normal. Relatable, even. Apparently she called him around 1 a.m. to get him to join her at the club. (Though she had to borrow former BFF Paris Hilton's phone as she couldn't find her own.) Hello, booty call! But it turns out that KFed was babysitting their kids at the time, so was unable to meet up. Doh!

We guess it's a new kind of rock-bottom when your ex-backup dancer slash litigious-ex-husband slash baby-daddy gives you the hand. On your freakin' birthday, no less. It's too late for Brit, but after the jump, we share ten booty call rules to help the rest of us avoid such humiliation.

1. Text messages were practically invented for booty calls! Slurring goes unnoticed, grammar is irrelevant, and if they're not around, you won't embarrass yourself with a rambling voicemail message.

2. If you're too drunk to find your cellphone, you're probably too drunk for a booty call.

3. If you're in the habit of drunken-dialing the wrong kind of booty call (that ex you can't get over, your boss, etc.) then choose a designated dialer and give them permission to cut you off at any time.

4. Paris Hilton is probably an unreliable designated dialer.

5. When seeing a booty call, stick around for morning sex but not brunch.

6. Staying home and making a sober booty call from your own bed and convincing someone to leave a bar to come service you is a highly underrated act.

7. Your booty call has jumped the shark when you meet up and just watch The Daily Show together instead of shagging like rabbits.

8. Bartenders make great booty call partners: they get off at the right time to get you off, they can serve you free drinks, and they are naturally blessed with a low commitment threshold.

9. Booty drive-bys (when you stop by their place at 2 a.m. because you can't find your phone or their number) are generally a terrible idea. We'll bet you a hundred bucks they're either fast asleep or entertaining someone else.

10. If he's home because he's babysitting your kids for the night, it's probably not a great idea to booty call him.

For even more rules, check out our booty call-themed Impertinent Question of the Week video.