Squat comfortably and, push your butt out and keep your back flat . Pick up a kettlebell and pass it to other hand between your legs. Repeat and alternate . You should feel the pressure in your hamstrings and feel well fixed on the floor.

At each pass brace your core and turn to the direction you are passing the kettlebell to.

You can either stay in squat position or stand up after each pass as in this video