Single-side press, anti-lean challenge built in.
Keep your hips square and don't let your torso bend away from the working arm.
Pressing one dumbbell at a time gives the working delt undivided attention while the offset load tries to fold you sideways, so your trunk works overtime just to keep you vertical. The triceps drive the final push to lockout overhead. Reach for it when one shoulder presses noticeably better than the other, or when you want a stability challenge hidden inside your shoulder work.
It exposes and fixes strength gaps between shoulders that two-dumbbell pressing hides, and the uneven load forces your body to resist side bending on every rep. Start each set with your weaker arm and match the reps.
Let it hang relaxed or rest it on your hip, whatever keeps your torso quiet. Do not swing it around as a counterweight.
Often yes, per arm, because your whole body braces behind one press. Just make sure the extra weight is not coming from a side lean, the rep only counts if you stay tall.
