For a true single leg I always try to get my penetration... if it goes well, I will grab the ankle and drive my shoulder into the knee to force hyperextension of the joint and "persuade" the opponent to lay down for me. If he sprawls well, I HOPE he doesn't crossface me and take my back. If he attempts, I abandon the grip on the leg. If he sprawls but doesn't crossface and we both wind up standing back up but I have high control on the leg (around the thigh) I will kick the s**t out of his posted leg, assuming there is strikng involved (not to shin or knee but right above the achilles tendon). If we are strictly grappling (no striking) I will go with what Migo stated above.... I will "corkscrew" down and in the direction of the leg that I have control of trying to "whip" the opponent down to the ground. I will also use the trip against the post leg.

Livingfiction is also correct... setting up a leglock from here is very viable, depending on how they are defending.

I have modified all of my takedowns so that I don't wind up in guard so a lot of wrestlers always wonder about some of the quirky things I do... like the position of where I post my head and such. I did this because I used to feel REALLY vulnerable in someone's guard (my passing was weak) so I tried to stay out of it. Now I am more confident in my guard passing and defense (Thanks Chainsaw!!!!) so my takedowns are slightly different from the standard ones that many of you are familiar with in order to stay out of chokes, guard and half guard.

Peace-
Cam