Slap-pop and thumb movement

I seem to have problems with slap/pop. I don't seem to get the idea of how to make the slap/pop
into "one movement". Done slow it works, but as two separate movements. After slap I can see my palm
moving back and then forward again for pop. I think that makes the slap/pop combination slow.

Also if I try to do it faster, my wrist starts to do more up/down movement than rotating movement.

Is my idea right, that the thumb should be used as a "whip" so that palm stops but thumb continues to hit
the strings and bounces back to "rest" position little away from the string? How do you stop the palm?
Any good exorcises?

It would be good to see a VERY slow motion slap/pop in video with maybe a "mind model" or description
of what happens or how does it feel.

The internet video seems to be typically too slow and a fast movement like slap
is "almost skipped".

Try keeping your pop finger in a fixed position.

Have you seen this vid?



The Max in the video is me btw

I think I haven't seen this before.
This is almost perfect. The only missing thing is angle perpendicular to the
bass body to see the rotating axis of the hand.

I actually got the impression that the hand is little bent in the direction of
the thumb and the rotating axis is at about the outer side of the little finger.
That also helps to keep the side of the palm from accidentally muting the strings.

Are my observations right?

Another observation: at the "rest"-position the thumb was quite bent away from the strings.

VERY helpful indeed.