Lately in my training, I've noticed that as i unify my yin tissues begin to feel heavy, full, and dense...like a dense sponge that is full of water. The yang tissues feel equally full but they are light and expansive. The more I recognize these feelings, the more I can mobilize the body with them. i.e. expand to absorb, condense to project. This feeling in the arms is increased by wrapping the elbows down while maintaining the same position of my wrist. The wrapping really amps up the fullness.