The Wall Drill
Why this drill
Standing up out of posture — early extension — is the amateur swing's quietest killer. A wall behind you turns it physical: keep the trail pocket brushing the wall through the downswing and the spine angle holds; leave the wall and you've stood up.
Setup
A clear wall. Set up in golf posture with your rear a hand-width from it, no club needed at first — arms crossed over chest.
The drill
Rehearse the backswing turn keeping the trail pocket against the wall, then swing down keeping first the trail, then the lead pocket brushing it — the hips slide and rotate along the wall instead of thrusting toward the imaginary ball. Ten slow reps. Then ten with a club at half speed, wall still grazing. The feel is of sitting into the swing; the payoff is space for the arms that early extension had been stealing.
One thought to take with you
Turn in the barrel your posture built — don't stand up out of it.