Ok, I've done plenty of square and round cakes covered with fondant, but I've never had to try carve a cake.
I just had a request for a TOOTH cake. I had a quick search for pictures but I don't know where I would start?? Is there a cake pan that I could use as a base? Its such a rare request, I wouldn't expect to be able to find many tools that can help me out here.

Will the cake be lying flat or are you talking standing straight up? If it's standing upright, I have no idea because when I think tooth I think top heavy on thin 'roots'. If it's flat and just looks like a tooth when you're looking down on it, start with all of your cakes stacked and then slowly start to carve away. It's best if you print a picture of what you're going for first so that you have a point of reference and also, cutting them after they've been chilled will give you a lot less crumb mess and an easier time. Rounded edges are hard (for me anyway), but the only way to carve a cake the first time is to settle down and give it a go. Just start slowly and get the basic shape you want and then work from there. Good Luck!!!

I always start carving on a split, filled and crumb coated cake. I take a toothpick or a skewer and draw my outline, or sometimes enlarge the picture and literally trace. If you need to fix, just smooth that area and start over. A tooth cake is a great one to start with. I have one in my gallery. After I carve, I crumb that raw cut area, and chill before final icing. I small serrated knife (for me) is the best. I bought a 4 pack of cheapo "steak" knives from the dollar tree and it is my favorite carving knife. Have fun!

Oh..btw..when you start carving..you'll never use a pan again! I threw all mine out! LOL