this reminds of when I used to play hide-n-seek at my friend's house whose little sister would play too. she was probably 4 or 5 and I was 7 at the time, and if I found her while my friend was still hiding, I'd pull my dick out my pants and wave it in front of her face or run at her with it so I could see her reaction and get a weird little rush.
In a different thread I remember saying that choking myself out in 6th grade was my first drug-like experience, but come to think of it, this hide-n-seek self-exposure and ensuing 'high' was more likely my first mind-altering experience.