Pigeon Pose (Eka Pada Rajakapotasana) is a deep stretch to open the hips. Depending on your specific tightness, it also stretches the buttocks, hip flexors, gluteus, and quadriceps. Pigeon is a form of a backbend so care must be taken to protect the back. It is not recommended if it causes pain in the knee. Here, down-dog transitions to pigeon.