Stretch it overhead and stabilize those delts.
Keep your ribs down and arms slightly behind your ears, don't let the lower back arch.
Pulling a band apart with arms extended overhead loads the delts in their most stretched, least trained position, the tension rises as your hands spread wide. Holding everything overhead also demands genuine shoulder stability, your delts are resisting the band while keeping the arms stacked and the ribs down. It is a small movement that builds the overhead control pressing depends on.
Your shoulders are running out of range so your spine compensates. Squeeze your glutes, keep ribs down, and accept a smaller spread until your overhead mobility catches up.
Excellent, it wakes up the delts and grooves a stacked overhead position before you load it. A couple of light sets before pressing is the classic use.
Light. The overhead position is unforgiving, and this is about control and stability, not fighting a heavy band with a bent back.
