Tiny band, big delt burn, one side at a time.
Keep the anchor arm still so the working arm fights the full band tension.
With the band looped around both wrists, one arm stays pinned at your side as the anchor while the other abducts against the stretch, so the side delt fights tension that climbs all the way to shoulder height. The anchor arm is not resting either, its shoulder works isometrically to hold position against the pull. Working one side at a time also shows you instantly if one delt is weaker or sloppier than the other.
Anchoring one arm gives the working side a stable point to pull against, so the band tension is honest and the reps are stricter. It also doubles the time each delt spends resisting, since the anchor arm never fully switches off.
To shoulder height, no higher. Above that the traps take over and the band tension starts yanking your anchor arm out of position.
Keep both wrists neutral and roughly in line so the band sits flat. If it still slips, use a slightly narrower or grippier band, or hold a small loop of it in each fist.
