I have somatic OCD too. I've spent many nights in the bathroom making sure I'm not sick to my stomach or bowels. I keep thinking something is wrong and I've got to make sure I can still use the bathroom and empty out okay. I do more than just check, unfortunately. I push and strain and stay on the toilet all night. I've been learning to start accepting uncertainty though.
I say a positive affirmation: "I am accepting uncertainty and imperfection, and I am moving forward because I'm done with OCD. It's not worth it to me anymore."
The thoughts and urges still keep popping up. So then I say "Silence Edvilster!"
I gave my OCD a name. The name is O.C Edvilster because OCD is an evil monster. Then I just use Edvilster for short. By the way, I stole this idea from the movie "Luca." The boys in the movie say "Silencio Bruno!" to overcome they're fears.
Doing this little step has really been helping me. And sometimes I just say "Silence!"
Basically I'm just recognizing it's the OCD, and just like the boys in the movie, I'm going to silence that fear and move forward. No reassurance, no more checking. Just telling OCD to shut up, then moving forward. When I move forward I'm actually doing exposure therapy.
Separating the OCD from yourself can be incredibly helpful. Giving it another name has helped me as well.
I'm still a long ways from being where I want to be, but this has helped me a lot. I hope this is helpful for you.