Drill the hinge groove with a light pipe.
Keep the pipe touching your legs the whole way, it teaches the bar to stay close.
Sliding a pipe down your thighs with hips pushing back is the RDL pattern distilled, the hamstrings lengthen under stretch on the way down and the glutes drive the hips through to stand. Keeping the pipe in contact with your legs the whole way teaches the single most valuable barbell habit, the bar stays close. It earns its place as the first hinge most lifters should learn and as a no-cost warm-up before deadlifts and RDLs.
Same hinge, different pipe position. Here the pipe travels down the front of your legs like a barbell would, which specifically teaches bar path, while the good morning holds it across your back.
A soft, fixed bend, set it at the start and keep it. If the knees keep bending as you lower, it turns into a squat and the hamstring stretch disappears.
When every rep keeps the pipe on your legs, your back flat and the stretch in your hamstrings rather than your lower back. If a pipe rep breaks down, a loaded one will break down worse.
