This video is an in depth look into the Basic Stacking Pass.
This is a very common pass that is taught to a lot of white belts. The reason this come so early in the curriculum is because it requires very little (if any) base whereas standing passing can make the students feel like wheebles.
Keep in mind that it is very important to have good posture in the Closed Guard. If you look at the positioning of my arms they are both straight with one hand dominating the chest and one dominating the hips. Both hands are very important but do completely different jobs.
The hand on the chest has a simple job, it keeps your opponent from sitting up into you.
The second hand, the hand on the hips, is the most important hand as it does it's best to dominate the hips (no easy task). This hand is instremental in preventing the Basic Armbar and Triangles. Furthermore in this particular pass it has the important job of making sure that the hips stay pinned to the floor. You should notice that even when I load my torpedo and then launch the torpedo I use that hand on the hip to keep them pinned. If at any point those hips come off the floor I need to return to the seated position with my base heavy on my heels and start over.
If your opponent has very strong and mobile hips and you can not keep that hip pinned to the floor then it will probably be a better choice to use another pass.
Once the legs are open make sure to put both hands to the floor. If one of your hands gets caught then it is a good idea to place the knee up in the middle and abandon the stacking portion of the this pass (and use an alternate ending). Make sure to reference the video for the belly flop, double unders and most importantly, pulling your opponent into your "table"