It's on the anus at the part closest to my scrotum
, so the front side, not the back side. When I gently touched it, it made the vibrating sensation. Just to be sure, I would continue to touch it, very gently, and at intervals and rhythms that I could be sure would correspond with the vibrating, and it largely did.
So, this is why I think this thing may be related. I don't know if it is a hemoroid, or what.