Being straight, homosexual, or anything else has nothing to do with what orifice you might want something stuck into. If that's your concern, than stop worrying about it. Anal pleasure from a strap-on, as I assume that's what you mean, is not just for those who are homosexual.
I could go into the scientific explanations regarding muscles which explains why anal pleasure is pleasurable, but that might be going a bit too far. Just know that it's physically probable for most people to find sexual pleasure from anal stimulation.
Bottom line, here: if you want to try it, then go for it.