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 remember

7. you don't look them in the eye

8. you get away with it

9. she says it's ok

10. you can please all of them

11. you go home afterwards and fulfill your duty.

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

13. it's with royalty

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

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

16. It's in a different ZIP code

17. you get paid

18. she's not human.

19. you change the sheets afterwards.

20. they're on top