1. Tell him that he basically is a copy of his brother.
2. Tell him it's weird he's taller, but still younger than Mario.
3. Imply that "Luigi's Mansion" is the only game about him...and it sucked.
4. Also tell him "Luigi's Mansion 2" will also suck.
5. Constantly remind him he stands in the shadow of Mario.
6. Chase him and yell: "SPAGHETTI!" over and over.
7. Tell him he would never be able to beat a level by himself.
8. Constantly remind him he's always player 2.
9. Tell him the colour green, which he wears, is a sign of jealousy.
10. Whenever he talks to you by your name, say: "That's Mama Luigi to you, Mario! *Weeze*"
11. Cling on him and repeat: "MAMA LUIGI!"
12. Remind him that he was never in Super Mario 64.
13. Tell him over and over that his surname is Mario's name.
14. Run over to him, say: "Gay Luigi?" then run off again.
15. Say to him he's only strong enough to beat Bowser Jr.
16. Constantly remind him that he looked so wimpy when walking in a dark room in Luigi's Mansion