Artemis BJJ (Impact Gym), Can Sönmez, Bristol, UK - 07/08/2014
The tripod sweep I taught earlier this week combines well with the similar sickle sweep: as always in BJJ, that almost certainly has other names (the most common alternative is 'hook sweep'), but I'm using the term from Theory & Technique (page 226). A good time to try this is if when you attempt the tripod sweep, they kick their leg free from your hooking hand. You could attempt to readjust to recover your position, but it is probably easier to pull yourself towards their other leg with your hooking foot, grabbing the heel on that side. Turn your body toward that newly grabbed leg, swinging your pushing foot over to that hip. With what used to be your hooking foot, chop back low on their other leg to knock them over.
Of course, the sickle works on its own too. Indeed, Rener teaches this before the tripod on Gracie University. The entry he shows is to hook their leg, pulling yourself in to grab their ankle, then switching into the sickle position: opposite foot on the ankle-grabbed side hip, then chopping low on their other leg with your remaining leg, using your calf or possibly your heel.
In order to get the angle, you'll have to turn towards them (or like Rener shows, hook their leg to pull yourself in. If you're going from the tripod, you'll already have their leg hooked). Note that when you follow them up after knocking them to their back, compared to the tripod sweep, your other knee will be raised. That means you'll need to make sure to shove their leg down and step over, enabling you to complete your knee slide. Remember, there is also the other option of trying the technical stand up instead.
Teaching Notes: I did both the hip thrust and the technical stand-up drills today, especially as I think for the sickle sweep the technical stand-up might make more sense. I'm still not sure which one I prefer personally, but it depends on body type, leg length and personal preference. Doing both of the drills hopefully meant the choice was up to the students. I also added in the open guard Kev drills where you spar with only two legs, then one arm and two legs, as I think that's always helpful for working on using the legs in open guard.