Cis-Male, nearly orgasmed from just rubbing my pubic mound a couple of days ago. Has anyone else experienced this?

Hello all, I'm a cis-male who, a couple of days ago, was rubbing the area above my penis while looking at porn. Seen this area referred to as the public mound or Mons Pubis. I normally do this to get an erection as it feels good. But this time it felt different. I was rubbing longer and with more pressure than usual and I went from flaccid to nearly on the edge of an orgasm in seconds.

I stopped before I could cum because I didn't know what it was. I wasn't touching my penis at all nor was I stimulating anything else at the time. I've looked around for other people having this experience and I've seen nothing, everything leads back to perenium stimulation which is not what I was doing.

Anyone with any experience on this would be appreciated, I'm curious what it was and kind of tempted to try it again if its safe to do so.