The butt wink is a term commonly used to describe a squat that begins with a neutral spine and ends with a posterior pelvic tilt. The name is catchy but your inability to squat properly is putting your low back at risk for injury. Follow this step by step guide to eliminating the butt wink and squatting pain-free. A Joint-by-Joint System to a Better Squat – The Low Back Files: http://buff.ly/2mLnHwe