Drag the weight up your body for a peak-focused squeeze.
Elbows go back, not forward, keep the dumbbells close to your body.
Driving the elbows back and dragging the dumbbells up your sides removes the front-of-shoulder swing that creeps into normal curls, leaving the biceps to do the entire job. The altered path keeps tension on the muscle at the top, where standard curls usually go slack. It is a strict, honest variation that suits anyone whose curl numbers grew faster than their arms.
Your elbows travel back instead of staying pinned or drifting forward, so the dumbbells stay against your body the whole way. That takes the front delts out of the lift and keeps the biceps loaded at the top instead of resting.
Because the cheat is gone. The drag path strips out shoulder assistance and momentum, so a lighter dumbbell delivers a harder biceps contraction. Judge the exercise by the squeeze, not the number.
Only as high as they can travel while staying in contact with your torso, usually around the lower ribs. Chasing extra height by letting them drift forward turns it back into the curl you were trying to improve on.
