This is a partner drill but with a little thought you can transfer it to a solo drill using a sandbag, a rock or anything else that suits your needs. you squat with feet flat on the ground as this is about alignment and not balance out of tension work and start to roll your partner which is prone in front or behind you with open hands or with fists as you wish back and forth and in circles which are important to grow a working understanding of how the body works. You change rolls and repeat and later on you can add using a stick or any tool you wish to add to the drill. Let the breath lead each movement and move as one using all that you have. If you are limbering and trying to work with just your hands or placing your hands and moving with just the legs than you are stopping yourself. Think about it and work honestly.