What Angi said
The pulsing in Callanetics is such a small movement that it is almost more mental then physical, does that make sense? When I'm doing Callan, I can barely tell the body part I'm working is moving, but it is and working hard I might add!
The bouncing during stretching that was done in the 80's was litterally bouncing hard enough to stretch the muscle farther than it's willing to go, which is a big no no as you could really hurt yourself.
I hope that helps.