Whats the best thing to use for anal stimulation?

Well, that's the best thing! Or butt plugs, but be gentle, don't just cram them in.

Fingers are a good start. They are small, and they can be wiggled for some stimulation. Some people prefer fingers over toys because of their nature. But if you do decide to get a toy, start with something small so that you don't hurt yourself, and make sure that is has a wide base so that it doesn't go all the way inside you and you can't get it out, otherwise you might have to make a very embarrassing trip to the hospital to have it removed.