The scientific name is "myoclonic jerk"
Usually it happens when you fall asleep but did not expect to fall asleep... You'll be conscious but with a distorted sense of space, so you get startled and have a natural reaction to try and get back on your feet. With enough development I came to find that they usually happen during tiny dreams that we tend to instantly forget. Waking up "violently" usually has that dream-erasing effect.
The fact that it happened is a good sign, you were right there at the gate but popped back out... What you'll want to do is try to stay there, right in the middle, not so awake that you're still feeling your physical body and seeing the darkness behind your eyelids, but not so asleep that you're unconscious. It's key to the whole thing, pretty much.
Usually it happens when you fall asleep but did not expect to fall asleep... You'll be conscious but with a distorted sense of space, so you get startled and have a natural reaction to try and get back on your feet. With enough development I came to find that they usually happen during tiny dreams that we tend to instantly forget. Waking up "violently" usually has that dream-erasing effect.
The fact that it happened is a good sign, you were right there at the gate but popped back out... What you'll want to do is try to stay there, right in the middle, not so awake that you're still feeling your physical body and seeing the darkness behind your eyelids, but not so asleep that you're unconscious. It's key to the whole thing, pretty much.