Squeezing legs while sleeping

So for as long as I can remember, I do this thing where I squeeze my legs together when I’m sleeping and I get this AMAZING feeling!!! I can’t do it all the time, maybe a couple of nights out of the year. it’s like once in a while. I’ll squeeze them then wait a few seconds and squeeze again. It’s the best feeling ever!!! Better than any sex I’ve ever had. I’ve been having these episodes for years. I am 28 years old. I feel like it used to happen more frequently and last longer. Is it some kind of stimulation? Anyone else do this ?