Okay. I agree with Echsos, I think sometimes people are thinking of the low single when they say anklepick too.
And:
No offense, but I didn't like either of the examples shown. I'll see if I can find any.
In the meantime, I'll try to describe how I prefer to do them. One way is pretty much like Echsos described: Off a collar tie and an elbow control tie or inside control tie. I think it's a fairly safe takedown to go for.
Here's another:
I'll get an underhook or hook around the waist on one side and inside control on the other. On the underhook side I hip in bump the opponents leg back using my leg that's on the same side (right hand underhook - my right leg bumping back the opponents left leg). We call it 'kipping the leg' but I have no idea what that means...
Anyway, while I hip in and drive my right leg in deep bumping his left leg back, I lower my level and pick his right ankle at the same time. If you've drove your right leg in there deep enough the ankle is practically right there cause you've gotten pretty low at this point. And it's pretty safe because you're controlling the hands with the tie up and you're blocking the opponents one leg with yours and you don't release the arm until you're ready to take the ankle and you shouldn't eat any knees before then and once you've picked the ankle you shouldn't eat any after. Worst case scenerio is you might fall into the guard when you hit the floor but I can live with that...
Anywaaaaay, I don't know if that description makes any sense or not. I hope so because I've had a lot of success with this technique so I really want to share it. I'll try to find an example of it if I can.