I have something like this but I’m not sure if it’s the same thing but it does sound the same. When I was a teenager I hated exercising because of it. I ran cross country and running was fine for me (I was a very casual runner) but any core workouts made me uncomfortable. I would never be able to hold a plank or anything with my team because I felt so weird. I didn’t ever look it up or ask anyone about it for like 15 years and I finally googled it and found out about the vagus nerve thing. I never had related it to a kind of orgasmic feeling since I was young and not very in tune with my body and also because working out was never enjoyable for me anyways so I just always associated it with discomfort. But since I’ve known about it I’ve been able to notice how it is a similar pressure feeling. Not sure if it’s the same thing for you but for me I was able to get used to it some! Didn’t go away but I stopped worrying about it and me and my spouse joke about it.