If you are afraid it will topple, it sounds like you may have not made a dense enough cake. If it is very light and springy, it makes it harder to sculpt and make it cooperate. But, if you have icing covering it and a dowel through it, it should be fine if it is only the size of an actual can. The best suggest I have is to cut more circles and squish the cake so it is a little denser. But, I don't know how well it will work. Good luck.
Music and cake make me happy!
Music and cake make me happy!