Held much too tight on her lap
I just love it when a woman holds me from behind with her hands kept pulled way back extremely tight into the soft of my stomach. Comes from getting held on laps that way a lot when I was a kid, blame a couple of older teenage girls in my environment.
When I was a boy, my teenage cousin always held me on her lap with her hands kept pulled back into my stomach a good inch to two inches deep. And I really liked how it felt, getting my stomach held in. She often did this openly right out in front of our family, and it was secretly affecting me in ways nobody (including probably her) ever recognized. But nobody ever thought anything of it, in fact they usually paid no attention to the peculiar way she was holding my stomach in.
This led to me getting my babysitter to hold me on her lap the same way, only with her hands kept pulled back into my stomach much, MUCH tighter. I cannot possibly exaggerate just how freaking TIGHT she always held my stomach in... so tight it felt like she was going to snap me in two. My babysitter was a big brawny farmgirl, and I think she found this a simple way to keep me entertained, and keep me held silent and still whenever she was watching TV. I loved it, though I know I would have died if anyone else had ever seen the strange abnormal way she was constricting my stomach in so horrifically tight!
As I grew older this led me also to experiment with tight belts. When I was alone in private I would pull my belt in just as tight as it could possibly go. I liked it a lot, and it was definitely inspired by my experiences with my cousin and my babysitter.