Help asking a guy to homecoming?

ok so the guy i want to ask graduated last year but i know he wants to go cause he was saying how its too bad no one asked him to sadies cause that means hes probably not gonna get asked to homecoming. Well i dont see him very often and i dont really know him that well. I see him pretty much once a weekend at my friends house cause he has a lot of parties so i dont really want to ask him face to face cause im really shy and there are usually a lot of people their so i was thinking i couold put something in his car or something. but idk what. I know he loves mountain dew so idk if i could do anything with that but i really need some ideas. Thanks!! and i will give a best answer :)