I don't know if anyone else has had this experience, but I had this unusual stim from the time I was a toddler. I have it on some home videos. I did it all the time. I remember doing it, and the feeling I got from it. It was a happy stim, the feeling was like extreme happiness, satisfaction, and excitement. I made sort of a weird face, and moved my fists in a particular way.
I would do it while drawing, watching tv, playing, or when anything made me really happy. I don't believe I really knew I was doing it. Until one day in elementary school, some kid pointed it out to me, and kind of made fun of it. I think I became embarrassed and stopped it sometime soon after.
I never really got anything to replace it. I still do some things with my hands, and/or jump up and down when I'm excited about something, or anticipating something good. But it's not the same feeling. It's not as intense, and there's something missing from it. I'm wondering if I destroyed something that helped intensify my feelings of happiness, and ultimately made it better.