You can enter this pose in different ways, but the easiest way to start is from seated. Lean towards one side, let’s say the left. Raise your right leg and hook the foot behind the foot – this will require some flexibility. You can hold on close to the top of the hoop for balance. When leg is straight and stable, slide your seat off the hoop slowly. Make sure to keep your left shoulder and arm on the back of the hoop. As you slide down the bottom bar should come to rest under your shoulders, and this position should feel quite stable and you can let go with your hands.
One option to come out is to raise the bottom leg up and into cradle.
A similar pose is called side star, but there your hips are behind the hoop.