This is, in essence, the combination of two different skills, which are linked to each other because of their nature. The roll is where you use the base of your foot to roll the ball back and forth or side to side, shift it around in order to confuse the opposition about where it’s going to be. We have labelled it as the Sole Roll on this site.
The inside-outside is exactly what it sounds like, moving the ball in such a way that you push it to the outside of your foot with the inside of your foot, then push it from the inside to the outside. Doing this over and over again can become part of your skills practice and should be incorporated into a dribble.
When you bring the roll into the skill, it helps to take it one step further. You should start with the ball on the inside of your foot before rolling the foot over the top of it. At that point, it will be on the outside of your foot and you can then roll your foot back over it in order to get it back on the inside. The major difference between this and the inside-outside normally is that you don’t take your foot off the ball, maintaining contact at all times. That allows you to ensure that opposition defenders can’t take it off you without potentially giving a foul away, which would obviously be ideal for your team if you’re in a threatening position on the edge of the box (or in it).
The more you can get used to performing the skill, the more likely it will be that you can start to perform it whilst on the move. You shouldn’t be afraid of struggling to keep the ball close to you initially, nor the idea that you might even fall over at some point. That is what practising on your own is for, giving you the chance to perfect the skill in your own time and without the pressure of an opposition player trying to tackle you.
Doing it again and again in that sort of environment will then put you in a much better position if you want to try to use it during a normal match, at which point it will have become second nature for you.