Butterfly pose is a foundation pose that stretches the groin and less so, the hamstrings, depending on how far your feet are away from you. To enter the pose, sit with back straight legs outstretched. You then bend your knees and bring your feet together and towards your body in one movement, sometimes it helps to guide your feet while cupping them with your hands. The deal progression for this pose to to have your knee flush with the floor and the feet only a few centimetres away from your groin.