This might help you feel it.
My right shoulder is painfull so yesterday i only felt my left side(hamstring, glute and lower back after 3 sets.
First set i just raised and hold about 60 sec. Rested about 55 sec. On a regular lower back extension where we end up horizontal not the one where we endup about 45 degrees.
Second and third sets regular repetitions but not going down all the way to maintain tension i only go down about 60 percent of the potential mouvement.
The trick is i was doing all this holding 20 pounds pressed on my torso ,only with my left arm,
Hopefully with enough sets/weight holded only by your left hand/arm you will feel it.
If not try first doing leg press to pre-exhaust your glutes and hamstrings and finish with lowerback extensions has described.
You might have to do it every other day for 2 weeks but it was a really strong definitely 1 side feeling i got so i would bet it should work. You might keep your right hand behind your back to make sure it is not working even unintentionally.
All the best!