“self pleasure” addiction, how do I stop?

So, it's been about 5 years now since I started. It's not normal, it's disgusting. I'm female and I'm pretty proud of my body and myself and who I am, this is the one thing I can't get rid of. I don't want to go into detail about what I do, but I'll try and explain vaguely. It's gross, it makes me feel good, I know it's weird and disgusting but I still do it, it only involves me and no one else, and it's legal. I do it everyday, I've tried to quit but the longest I've ever made it was a week. I'm too ashamed of it to even go to my therapist about it because I know I'll see her again, and it's something I know she probably hasn't dealt with before. I need help on how to stop, please, someone give me advice.

Edit: It's masturbation, but not in the place you usually do it. So I'm just going to say it out loud because I do need to get over it, it's anal masturbation. I'm heavily ashamed of it. I need to stop.