Increase the Range of Motion of the Hip and help stretch your Adductors AKA groin muscles. This will help improve your Lateral movement, Lunges and Squats.
You can use your hand to help press the knee out wider. Or rotate through the torso and reach the arm up towards the ceiling. This will rotate the hips slightly and create External Rotation in the Hip Socket.
Stay out of the Pain Cave, You will want to keep modifying your position until your feel that you have found a stretch that works the best for you.