I think “jumping” is the right word. I can be laying on the couch ready to take a nap and as soon as I start to fall asleep I get a jerk reaction periodically. It only jumps/jolts/jerks once, and then perhaps a couple minutes later my whole leg does it….then my arm….sometimes my whole body. But it only does a single jolt (thank goodness). Once I’m asleep, I don’t notice it. I fell asleep on the beach one time a couple years ago and my husband was like, “Honey, you were flopping around like a fish”. We had a good laugh…because I told him I was afraid to fall asleep under the umbrella on the sand because I’d probably start jumping around. It was worth it. Best nap ever…who cares what other people saw. I don’t. :)