Sensation behind the balls

I’m worried about a sensation behind my right testicle between the anus and my testicles. It doesn’t hurt but it’s a weird sensation like it’s tightening. Is this due to over-doing the stretching a bit or what?

If I get an erection and grip the shaft and kegel I can feel a sensation as if I was pushing my finger between by anus and testicles.

Anybody have similar experiences?