I have never done JM presses but this is the 2nd post i have seen (one on another forum). Will have to add these in
It's worth watching videos that demonstrate one or two variations, as well.
In one of Jim Blakely's originals, he mentions that that the technique he demonstrates is THE JM PRESS the way HE invented it. But, he also then goes on to say that there are other "versions" that are slightly different, but he feels are quite effective for many trainers.
Many videos will contain "JM Press" in the title, but if you're interested in seeing the true Jim B. original:
edit: For some reason, I've been having issues imbedding youtube videos. Here is the link instead: