There's a really useful video by Scott Devine on this one.
https://m.youtube.com/watch?v=VmBy7XA0ceI
For me it boils down to- reach pinky, slide to next note, cross string and repeat. Reverse for descending.
As to why, it's always useful to be over capacity in terms of technique, it affords a degree of grace that is more pleasant to listen to. Think Ferrari doing 100 miles an hour rather than a Ford Focus. You cover the same amount of ground but i believe the former would be more graceful!
If you want to hear this in action have a listen to the numerous play along videos springing up to Vulfpeck's Dean Town. They can play it, but Joe Dart's over capacity technique affords him the opportunity to put more inflection and style into the lines which gives it so much more life. (At least to the plays alongs I've watched so far, and if I did one I'd view my own playing the same way!)