how to stretch the psoas muscle
A towel stretch is an effective way to stretch your psoas muscle. You can use a regular bath towel or a strap that's roughly the same length. To do the stretch, lie close to the edge of your bed on your stomach. Plant your outside foot on the floor and bend your other leg.
Stretching your psoas muscle lying down can be done on the floor, but it works best on the edge of a training table or bed. Lie on your back toward the lower end of a table so that your buttocks is at the edge. Allow one leg to hang off the edge as you grab the other knee with both hands.