Hi and welcome, @kapadu1408 !
I have OCD in the form of germophobia. I can tell you that if it's not addressed, the intrusive thoughts become worse and more entrenched.
I've heard that part of OCD can be an obsession with private parts and sexual acts, and that this can completely take over your life. Like any of the obsessive thoughts of OCD on whatever topic, germs included!
The recommended therapy for OCD is called Exposure Response Prevention therapy, or ERP. It's like if you're afraid of spiders, you expose yourself to them in small doses and gradually work through your fear of them. Then you expose yourself to spiders gradually more and more and see that nothing bad happens to you, and that's the way it works.
To be honest, I have found that ERP is very, very difficult and confronting...I get terrified that my whole house will be contaminated with germs and no longer be 'safe' for me!
But I do recommend that your intrusive thoughts get addressed before you become completely obsessed with sexual matters in your head to the point of becoming non-functional in your daily life. Do you have any professional mental health support? Like a trusted GP, counsellor, psychologist or psychiatrist?
If you visit your GP, they can sign you up for a Mental Health Care Plan (MHCP), which entitles you to 10 (20 during Covid) subsidised sessions with a psychologist per year. I would definitely recommend this. However, the catch is that psychologists are so overburdened at the moment that you will be waiting months to get in to see someone, probably 6 months at least. Plus a lot of psychologists aren't taking any new patients at the moment.
So the sooner you can get on to this, the better, I reckon.
In the meantime, I want to send you my empathy...I know your intrusive thoughts aren't under your control...and also that they are very powerful. When I feel the need to wash my hands, nothing can distract me, and the panic gets bigger and bigger if I am somehow delayed from washing or sanitising my hands.
I don't actually know how the ERP therapy works in regard to sexual thoughts, as you would be exposed to other people all day long in your daily life...so I'm sorry, I can't help there 😞 But I do want to commend you that each day you get through with only looking at people's private parts, you are keeping a lid on the thoughts, as they could grow and become an obsession with lewd acts. I have heard that people with this condition find it very distressing.
A handy forum tip is if you type @ and then click on a name in the drop-down box, that person will get a notification and won't miss your response to them.