First we worked on our basic scissors sweep, from guard. Step by step, the first thing you want to do is make sure that your main grip anchor is set up properly. You want to have an outside grip on their collar, with your hand deeply sunk in to the cavity created by the collar and the nape of the neck. Your other hand needs to be controlling their outside arm, hopefully creating a situation where it is impossible for them to post (support their weight, block movement) with that arm. Your legs start in open guard, and depending on the momentum of their forward drive, you may need to either hip escape first, or shrimp away to get a good leverage point for both your legs on their body. Opposite to their outside arm (that you are hopefully controlling) you should be sneaking your knee in to get a nice control point on their trunk. Your other leg, should be preventing them from shifting their base, usually a nice way to do this is to just pop your foot onto their knee, or right beside it. Now, without getting too comfortable in the one position,. because you really want the movement to be as dynamic as possible, you need to pull their body toward yourself, with the ideal goal of them 'falling' forward and attempting to post with the arm you are controlling, and at this time, create the leg sweeping action by literally chopping with the 'scissors' created by the position of your legs.
After the basic sweep, we started drilling a reversal to a stuffing of this sweep.
The sweep was stuffed by using the other (uncontrolled) arm, to brace against the knee, and thus prevent the shifting of the weight. In this situation, you wanted to two-on-one control the inside sleeve, and drive it across your body to the ground, where you can take the back with an over-reaching underhook. At this point, you simply need to roll backwards to take them into side control.
That's all the technical drilling we did, and spent the rest of the night (an hour) rolling.
It was boss.