Squat to your real depth
Have someone film you from the side and find where the pelvis starts to tuck. Stop just above that point for now. A clean parallel squat beats a rounded rock-bottom one every time.
Butt wink is your pelvis tucking at depth; fix it by only squatting as deep as you can hold neutral, plus mobility work.
Butt wink is your pelvis rounding under at the bottom, usually from limited hip or ankle mobility or squatting deeper than your control allows. First, only descend as far as you can keep a neutral spine, then rebuild depth. Work ankle dorsiflexion, widen your stance slightly, and brace your core hard throughout.
Have someone film you from the side and find where the pelvis starts to tuck. Stop just above that point for now. A clean parallel squat beats a rounded rock-bottom one every time.
Limited ankle dorsiflexion forces the pelvis to compensate, so test it with a knee-to-wall and work on it. A slightly wider stance with toes turned out gives the hips more room and often removes the wink instantly.
Take a big breath into your belly and brace before you descend, and lower under control rather than dropping. Keeping the trunk tight helps the pelvis hold neutral deeper into the squat.
If squatting causes back pain rather than just the visual tuck, stop loading it heavy and see a physio to check your mobility and technique.
Butt wink is your pelvis tucking at depth; fix it by only squatting as deep as you can hold neutral, plus mobility work.