Here is a basic exercise to help you overcome this technique:

Implementation

You can implement this technique on any scale you want, and progress your runs on as much strings as you like. For beginning, start from root note, and once you got the technique in your fingers, improvise in all modes you know.

I came up with a couple of interesting runs. Once you learn each individually, you can try and combine them!

I strongly advise you (as I always do), to not take these exercises only as they are. Take your scales and licks and implement! You will be surprised with how exotic it will sound!