I've been recently working on the double thumbing technique, the one that Victor Wooten often uses, and I'm not sure if I'm doing it right, specially concerning the first approach on the strings.

When I hit the string going down with the thumb, do I hit it as if i'm slapping the string and just let my thumb rest on the next string or can I just keep my hand on the strings and just pluck the string down and then up?

Basically do I have to hit the string when going down with the thumb?

Thank you for your help.
You don't have to.

Best thing I ever did when learning the Double Thump was to imagine your thumb as a pick
"Whats that noise??"

"... Jazz"
Hey i just tried that and you're actually right, my movement is becoming more smooth, thanks for you help!