Circle the bell around your head, then crunch to the side.
Keep the halo close to your head and let your obliques drive the side crunch.
Circling the dumbbell around your head makes your core brace against a load that keeps changing position, then the side crunch asks the obliques to finish each orbit with a hard lateral contraction. The combination trains the trunk both ways it earns its living, resisting movement during the halo and producing it during the crunch. It packs a lot of core work into one standing drill with a single dumbbell.
Light to moderate, something you can orbit smoothly around your head without your ribs flaring or elbows scraping past your ears. The crunch is the loaded part, the halo is the control part, so let the weaker of the two set the weight.
Yes, as written. Halo one way, crunch to one side, then reverse the circle and crunch the other way. Alternating keeps both obliques and both shoulders working evenly across the set.
Small and hard. It is a side bend of the ribs toward the hip driven by the oblique, not a full-body lean. If you are tipping over from the hips, shrink the movement and squeeze harder.
