When I've got the harness grip, if I can put them on their side like this, I only need to keep one hook on the same side as my choking arm. In this case, this is his right side, my right hook and my right arm. My left foot is free to do different things. I could just put it in as a hook like normal, or I could do this:
I am stepping on his hip (to keep him turned on his right side) and I am pinching the side of my knee down on his left arm, pinning it to his ribs. I could use a one-on-one grip to pass his arm down to do this, but I just skipped ahead for this photo. This is a surprisingly strong way to trap the arm since it holds it in an awkward position.
If they do straighten their arm to escape, you can hook it with your leg, like this:
Now he's foyally rucked. You've now totally killed that arm, and if he takes out your right hook, you can still switch to the crucifix.
What makes these work so well in combination with the stupid simple sweep is that when they posture back and trying to pull their arm out, they actually give you something solid to climb in order to get on their back.
God, I'm just totally awesome.