It's always tough when it comes down to this. It's hard on the snakes and it's hard on us. I can't count the number of times I had to restrain a snake for whatever reason, in spite of it's violent protests. The goal is to get the job done without injuring the snake. Set aside the trauma for now (Yours and the snakes) if something needs to be done. Steve's advice is sound. If you must restrain a snake, especially by the head area, it's best to keep the rest of the snake from twisting, flailing, etc. to reduce stress on the spine. Sometimes what must be done must be done. Sometimes they aren't going to like it, and you're not going to like it. What's left is getting it done with minimal risk of injury.

I cringe and grit my teeth anytime I have to forcefully restrain a snake. I don't like doing it, and I'm sure they don't like it. But when it's for the better (treating an injury and/or possibly saving their life) it's worth the effort and worth doing it right.

I can tell you I've done it. Force feeding, medicating injuries in awkward places, etc. Sometimes, just sometimes, it results in saving a snakes life. That makes it all worth while. Sometimes, in spite of the effort, the results aren't good. Sometimes you just have to try where doing nothing looks like it will end badly.