Is it anything like this?
https://youtu.be/J1ueQaJSOIg?t=6m44s
the pass attempt is going to come on pretty fast in the video where I've linked to it: a couple seconds. Marcelo isn't turning his whole body, just his hips. In the video, Eddie pivots to get the right angle to rehook the lockdown, forcing Marcelo to try something more complicated (and maybe risky).
This is my favorite way to pass lockdown half because it's so simple and takes advantage of shoulder pressure.
Here's how I try to counter it (take whatever dose of salt you want with this advice)
My outside leg is crossing his leg and my inside leg is applying the lockdown. He's unhooking the lockdown and pivoting to screw up the angle so I can't lock him down anymore (because my legs aren't strong enough to bend his knee sideways).
Odds are good that his foot is now pointed in the direction of my outside leg and is flat on the mat (just like you see at 6:46)
I like to apply pressure with my outside leg to put some downward weight on his knee joint (trying to bend it). The other foot pushes on his ankle to bend the leg. The pressure twists his leg in an uncomfortable way (the same tortion that Lucas Leite likes to apply when he's playing Dogfight). One way to relieve this tortion is to allow the leg to bend. When the leg is bent and that angle returns, I can lock him down again.
When you're pushing the ankle like that, I think some care is required: I am sure that you can hurt your opponent if you contort his leg with sudden force.
BUT: the angle is such that he's essentially in knee slice position. If his pressure and angle are correct, he may be able to slice through. I feel that this is a risky pass attempt as he is leaving himself vulnerable to a sweep if he gets caught up at all. With his leg contorted, simply increasing the contortion will force him to accept a sweep. But people who are better than me are sometimes able to slice through at this risky moment.
Hope it helps. If you can describe your opponents arm configuration (Head and arm? Do you have double unders? Does he?) and where he is putting his pressure (on your sternum? on your neck?) it will help us understand the posish a little.