Okay ummmm.....I am 13 and I can not stop thinking about doing oral sex to my self ?

I need to no a way to stop this as I got exams plc help me or tell me a easy way to do it and I think I might start my period soon but is it to young at 13 to finger my self or any thing or is there a way that I don't have to finger my self as in not puting my fingers in (plz help)xx