0. When you see him gasp and say "So L really DOES have an evil twin!"
1. Replace all his strawberry jam with cherry and raspberry.
2. Tell L/B that they're reflection is stalking them.
3. Innocently point out the fact that B+L=BL (Boys love).
4. Do not ever flush the toilet. (Yeah, yeah I'm immature)
5. Sign him up for a therapist. And and drag him out to see him/her.
6. Tell him that Naruto/Inuyasha/Yugio/whatever manga you like is way better than Akazukin Chacha, and start a fan war about it.
7. Every time he walks into a room sing happy birthday. And when he says to stop say "but it's your theme song!"
8. Ask him very seriously if A liked tacos.
9. Ask "Why do you cosplay as L all the time?"
10. Ask if he hides under beds because the monsters are the only ones that understand him.
11. Ask if he drinks blood.
12. Ask him if a Shinigami dropped its eyes or if he attacked one and stole them out of its head.
13. Act overly superstitious about #13.
14. Say you thought that cloning people was illegal
15. Replace his sugar with salt before he puts it in his coffee.
16. Handcuff him to L.
17. Shave his head and say he's Voldemort.
18. Take a picture of him, and try to use one if those red eye pens on it, then complain it's not working and you're suing the pen company.
19. Steal all his shirts and replace them with straitjackets.
20. Ask if he's just the girl form of L, and hold up his makeup and shojo for proof.
21. Ask "are you upset that L has a new boyfriend...the guy that killed you!
22. Don't die.