1. they look similar. then it's just a tribute.
2. it's with a celebrity
3. they're twins
4. you spread peanut butter on your balls and your dog licks it off
5. it's a threesome
6. you don't remember
7. you don't look them in the eye
8. you're in a different area code, not to mention a different state.
9. she says it's ok
10. you can please all of them
11. you get away with it
12. it was actually them but you were thinking of someone else
13. it's with royalty
14. you get paid
15. you change the sheets afterwards.
16. It's in a different ZIP code
17. you have two girls at the same time, so one invalidates the other.
18. she's not human.
19. you go home afterwards and fulfill your duty.
20. they're on top