It also doesn't have anything to keep its teeth in line when it chews... I think this is one of the mysteries of yukkuridom that we shouldn't let get in the way of our schadenfreude.
Come to think of it, I don't think I've ever had a manjuu; the closest I think I've had are the steamed pork buns I make from a dim-sum recipe. Oh, but those are good... Actually, I might have to make some this weekend.
It depends on the manju. The good nice ones with the soft skin will tear open and splatter, the cheap ones that's all skin and no filling will be perfectly ok. Also it's not like you drop them on purpose, sometimes shit just happens. >_>