Warmup: Frog Squat
With feet at shoulder width or slightly wider, put your elbows inside your knees and push them outward.
Sit your butt down as far as you can while pushing your knees out and maintaining as straight a back as you can (some curve is okay!)
Push your butt up as far as you can without moving your elbows from your knees.
Repeat! Try to increase your range of motion a little bit with each rep.