Hey vampire,
I have always been fascinated when a see a girl hanging from the monkey bars. The best is when there are wearing a shirt that completely covers their stomach until they jump up and hang on the bar. When they are hanging the shirt pulls up above their pants or skirt so that their stomach is showing.
One of my favorite memories is when I was at church playing in the back area before Sunday school. One of the girls who was a few yrs older than me was back there with her friend. She was a cute redhead girl. She was wearing a nice skirt and top. When she hung from the bar her shirt pulled up to show about 3 inches of her stomach and a round bellybutton.
She hung there for a few seconds so I had time to walk up close and look at her tummy. Very cute and probably ticklish.
Other times I have seen a lot of belly when girls hang from the bars at a park near my home. Sometimes the whole belly is exposed for everyone to see.