Assuming you have a screen top cage, you can secure the probe inside the cage to the screen dangling down a bit directly under the CHE's path and it should be fine. What you do not want to do is keep the probe on the substrate where the snake can coil up around it or relieve themselves on it. Dangling it like that might get your snake to play with a bit but they won't lounge on it.

I did this back when I had an exo terra and it kept the CHE under control. Just made sure the wire did not hamper the screen from locking and zip tied the probe wire to the screen and dangled the probe tip about 3 inches below the screen.

Of course if you have to remove the top of the cage to get to the snake as in you do not have like an exo terra cage that also opens in the front doing this might be an issue. So if that is the case, you can dangle the probe on the side of the cage and secure it down outside the cage with sturdy tape like duct tape (you don't want tape inside the cage) or inside the cage if you can find a way to zip tie it. What you want to do in this case is make sure the probe doesn't move around much at all when you remove the cage top. This might not be the most ideal means to control the heat (ideally you want the probe directly under the CHE) but it will get you some level of control

The main thing you need to be aware of is not compromising the locking of hte cage so the snake can't get out and making sure the snake can't lay on the probe or pee on it. Anything else should work fine. Best case is directly under the path of the CHE but not touching the CHE of course.