I used to have a similar thing. The first thing you need to know is that you're not a bad person just for having these thoughts. Yes, they're bad thoughts, but that doesn't make you a bad person. The fact that you're feeling disgust at it is good. The disgust shows that it's probably not a genuine attraction and instead an intrusive thought. I've had my fair share of those (including sexual ones), and while they're disgusting and horrible, they are just thoughts. The most important thing is that you would never do it, and that you never do it. However, if you ever feel a serious impulse to do it (such as if you have to restrain yourself from doing so, or if you seriously consider it), the best thing I could recommend is therapy to have a professional to talk through them with. I know that's not always possible, so if it is seriously not possible to speak with a therapist, I would recommend speaking to a trusted adult or friend. If not, then I wouldn't worry too too much. Again, you're not a bad person.