O.B. Left, I did exactly as you explained in your right arm drill and was impressed how well it started to feel after a while. It has helped me to understand how basic motion should feel. After I got home from practicing the drill you described, my dad came by the house and wanted to got to the driving range. While at the driving range, I did nothing but what I understand acquired motion to be, while focusing on the #3 pressure point and, voila... the feeling of compressing the ball like it used to feel was back. Now I know I have a long way to go but it sure did feel good to start compressing the ball again.
I started thinking about it and think that when my swing started losing compression last year, without knowing it, I started swinging "harder" to get that feeling back and it just made me cast the clubhead even worse. Maintaining the #3 pressure point really helped with my rhythm also. Going to work on basic motion again tomorrow and continue the journey.
Glad it worked for you. I warm up that way every day and go back to it whenever the wheels fall off (almost every day). Homer called Lag, Golf's Secret. The feeling of Lag at #3 is really the clubs Longitudinal Center of Gravity, the Sweet Spot Plane that stretches from #3 down through the clubfaces sweetspot that is lagging the hands. Not just the clubhead. Focusing mentally on Lag at #3 and driving it indirectly into the ball is focusing on and aligning the sweet spot plane to the ball. It feels sweet too doesn't it? This is where the rubber meets the road, so to speak, golf wise.
Please read the comments by Drewit and Yoda above. They have added some additional important information (which might be endless actually, depending on how much you want to know or how precise you want your game to get). Pressure point #3 is not a direct drive pressure point but #1 is. Trace a straight plane line with Three Dimensional Impact being the goal.
I discovered the bent right hand (the companion to the flat left wrist) on my own while chipping with a cell phone held to my ear with my left hand. Perhaps the best chip Id hit in a while and so it became a drill for me and begat a quest to find information or schools of thought on the bent right hand. A journey that ended right here. LBG and TGM have added many insights to go along with the singular notion of a bent right wrist. Things I never would have discovered on my own if I lived for a thousand more years. The On Plane Right Forearm, the Lag Pressure Point, Tracing a Straight Plane Line, Three Dimensional Impact (hit the search button for more info) etc etc and still adding some, too. I don't know how Mr Kelley discovered all of this information while in his garage for a decade or three. A truly amazing story.
As for losing your compression, Homer also said that "over acceleration is the menace that stalks all Lag and Drag". So swing slower and shorter when trying to find your swing, then ramp it up incrementally until you reach your normal distances. Luke has posted that to find you ideal, normal or everyday swing speed, swing slower and as shorter until you start losing distance. (Longer than normal shots,drives say are a "special procedure" an extra gear with the usual accompanying loss in precision to be accounted for)