I dunno if I’ll succeed with this explanation, but here goes….
When I’m doing DB rows as I’m pulling the weight up, I slightly twist my torso too. So if I’m rowing with my right arm and I start to twist; my left shoulder will dip down towards the bench while the right shoulder opens upwards.
During this slight twist you should feel your lat begin to tighten. I will hold this position, squeeze my lat until it burns while holding the weight. Then slowly lower it back down still flexing my lat.
Did I just make things clear as mud?
Cage