[Tcoudi]

Hello, sorry, this might be little bit clumsy vocabulary - wise from my side.
I would like to learn how the " simple" down up arppegio , its noted as vertical wavy line. i can do it sort of with my thumb or with a pick, but that move P i m r in correct speed i cannot pull literally for years. is there some video lesson or article that explains how to practice this? as i mentioned, i kinda fail to find right word in english for this technique. thanks.