I see a lot of different forms and ideas on this. I’ve included a video of myself squatting at the bottom of this post.
The basic idea is to get full activation out of your glutes and hams to drive the movement. Many people “rock forward” or overly bend forward due to lack of flexibility. I was one of the worst offenders. Which gave me an oversized lower back, and oversized quads. This also severly limited my core activation during the exercise, and my rear chain (butt and hamstrings) wasn’t doing enough work.
Leave your pride at the door, sit into the squat fully, go below parallel, and see your results exceed your expectations across all lifts and in the mirror.
Take a look at this video, tape yourself sometime with and without weight, and have fun doing the king of exercises. Just clink the link below to check out the video.