The reverse cascade is what happens when every throw is made Over the top. The reverse cascade is a normal cascade juggled backwards. If you videoed yourself juggling a cascade & then played it in reverse this is the pattern you'd see.
You can learn this pattern in the same way that you learnt the cascade. Or you can just work up to it by making more & more throws over the top until all throws are going over the top.
An over the top throw in a reverse cascade is slightly different to an over the top in Juggler's Tennis. In the previous over the top tricks you have been throwing from the outside to the outside. If you do this for a reverse cascade, your pattern becomes higher & wider with every throw (which can be quite fun but it soon becomes unmanageable). Juggle a regular cascade & pick a ball, as you catch & scoop to throw the ball just stop & hold it at the point where you would normally let go. Just let the other ball drop. Where you are holding the ball is the point that you need to throw to for a reverse cascade. If you used your right hand it should be a little way to the right of the centre of your body. All throws are thrown from the outside & caught on the inside.
It may help to imagine a ring horizontally in front of you at about neck height. Throw so that the balls pass outside the ring on the way up, peak above the edge of the ring & pass down through its centre.