1. they look similar. then it's just a tribute.

2. it's with a celebrity

3. they're twins

4. it's a threesome

5. you spread peanut butter on your balls and your dog licks it off

6. you don't look them in the eye

7. you get away with it

8. you don't remember

9. she says it's ok

10. you can please all of them

11. you're in a different area code, not to mention a different state.

12. it was actually them but you were thinking of someone else

13. you go home afterwards and fulfill your duty.

14. you change the sheets afterwards.

15. you get paid

16. you have two girls at the same time, so one invalidates the other.

17. it's with royalty

18. It's in a different ZIP code

19. she's not human.

20. they're on top