"Oh don't rub your hair on the wall."

Actually, I think I can expand this to include, well, everything. Honestly, I can't think of a single thing that needs to be rubbed on a wall. Nothing. Maybe there's something out there that might benefit from a good rub on a wall but I've gone through a long list and not one of them qualifies. However, I might be persuaded to narrow the field a bit and state that no body part should be rubbed on a wall. But if there were some object that you felt should, for some reason, make this sort of contact, then I suppose it might be alright if this rubbing occurred. Who am I to judge, right? (weirdo)