Always remember to exercise your better side first.
While lying on your back at the very edge/side of a bed or table, let your leg closest to the edge hang over. Without holding your breath, gently tuck the top of your pelvis back and down towards the bed. Hold this position with your pelvis while you bend your knee (of the leg hanging over). Keep your knee bent as you use the muscles of this leg to push it towards the floor while pulling it back. Hold for a 3 to 5 count. Let everything relax for a 3 to 5 count. Repeat for 8 repetitions.
You should feel a strong stretch on the muscles in front of your thigh. This transfers up into your pelvis to stretch your psoas muscle.