Hand or foot: reach there, the limb bends to follow
Forearm or shin: the spot you grabbed goes where you drag it; the elbow or knee bends and the hand or foot comes along
Upper arm / thigh / knee: swing the limb from the joint
Hips: move the whole body; the rings roll and turn it. Belt: arrows slide the body straight up, sideways or forward. Chest: bend the torso. Head: turn it
Double-click a hand or foot: pin it. Near the other body it becomes a grip and follows that body
Right-click a body: pick any part, even buried ones, and turn grips on or off. A picked part gets a yellow handle you can drag.
Mouse wheel while dragging: push the part away or pull it closer
Rings: twist the selected joint precisely. Forearm, shin, elbow and knee get a single bend ring, or use the Bend slider in the panel
Contact: switch from Pass through to Collide so the part you drag stops at the other body. Loose leaves room for chokes and tight entanglements