It is really important to position yourself properly when doing any hip flexor/ psoas stretches in order to maximize on the benefits of the movement!
Engage your glutes and thrust the hips forward.
Use slight rotations in the upper body to reach different angles.
Make sure your arm is extended upwards in order to open up the front fascial lines that are being affected.
Small dynamic movements forward and breathing is very important while going into the stretch.
Stretch out those hips
Make sure to spend 30 - 45 seconds on each side while doing controlled movements!