Wring out a stiff lower back, one slow rotation at a time.
Lead with your ribs, not your arms, and keep your hips facing forward.
Rotating your torso side to side from a tall seated position takes your lower back and the muscles around your spine through gentle, controlled rotation, one direction at a time. With your hips anchored to the floor, the movement has to come from the trunk itself, which is what makes it useful for unwinding stiffness after training or long hours in a chair. Slow and tall is the whole game.
A bit of both. Done slowly for reps it mobilises the spine and works the muscles that rotate your trunk, and pausing at the end of each turn turns it into a gentle stretch. Either way, control matters more than range.
As far as feels comfortable while sitting tall with your hips facing forward. The end range should feel like a stretch, not a strain, and cranking further with your arms defeats the point.
If your hips turn with you, the rotation comes from everywhere except your spine and you get nothing from the movement. Anchor your sit bones, lead the turn with your ribs, and keep the twist in your torso.
