You are essentially advising to bend and straighten one's arm simultaneously.
Have you taken leave of your senses?
I'd say yes and yes.
-with the inert left arm acting as a check rein, it can be done. Im doing it right now, try it. Grab ahold of your left thumb with a golf like grip of the right hand and use it to apply some outward pressure on the left thumb in a direction inline with the left arm and then bend your right elbow. The left arm should move across your chest as the right side of the triangle shortens. Like Magic.
-given Brian Gay's 10 shot win yesterday (nice extensor action on that fella)