Pinching & bending (AKA Supercropping) is when you take a section of soft stem between 2 fingers, and give it a squeeze until you feel a "pop" in the stem. Then you give it a couple gentle bends back & forth... This causes soft weak stems to get stronger at the pinch points (you'll noticeably feel the hardness a few days after the pinch); it helps out farther down the road, when there are heavy buds that need to be supported
I do that too sometimes, and it definitely works.