Losing control over my body due to certain touch

The tag "sensory issues" is not perfect for this, because I kind of like what happened, but I guess it was still the best fit.

Yesterday I experimented a bit with someone I'm seeing right now and I found out that I really like to be touched and kissed on sensitive places. Actually it was kind of too much for me and a little bit of pain (about a 5 out of 10) or overstimulation was involved at some point, but exactly that made me lose control over my body and I was moaning and twitching uncontrollably. It kind of made me... happy?! Like in a bodily way.

I'm kind of losing it just now remembering what she did and waves of ecstasy flood my body. What is that? Is that autistic joy? Is that maybe stimming? Is that just normal and I had no idea about it? Oh... and am I maybe a masochist??