Some does it, some doesn't. It depends on what you enjoy. I'd avoid the word "normal" tho. There's too much variance to be able to say if something s normal or not when it comes to human behavior. I'll say though, don't try to put something that might break or get stuck up there please. I have seen way too many cases coming by ER where someone got frisky with all sorts of vaguely phallic shaped things. Please, use things that's intended for that.