If you play a melody and have to jump to a neighboring string within the same fret, you can use a finger roll so you don’t have to change position.
![](https://fretello.com/news/content/images/assets-old/finger-roll.png)
To do this, play the first note with the tip of your index finger. Then to play the second note, simply roll onto the flat of the finger to press the b string in the same fret. This motion is only done by the finger itself, don’t do it with your wrist or arm.