Kneel on all fours, with your knees under hips and hands under shoulders. Don’t over-arch your lower back. Keep your neck long, your shoulders back and don’t lock your elbows. Slowly take your bottom backwards, maintaining the natural curve in the spine. Hold the stretch for one deep breath and return to the starting position. Repeat 8 to 10 times.

As a physiotherapist, I get asked this question all the time. Physiotherapists pride themselves on being able to provide their clients with research & evidence based treatment options.
So time to answer a few nagging questions.