Lie on floor with one leg extending up onto side of wall or column and other leg bent with foot on floor. One way this can be position can be achieved in a single motion is by sitting on floor with back of one shoulder against end of wall or column. Rotate body 90° onto back while swinging one leg up onto side of wall or column, ending up with back on floor and head positioned away from wall.
Straighten elevated knee until slight stretch is felt in back of thigh. If no stretch is felt, slowly straighten bent leg until slight stretch is felt in back of thigh. Hold stretch. Repeat with opposite leg on opposite side of wall or column.
Those with greater than average hamstring flexibility may not find this stretch to be effective. In which case, an alternative stretch would be more suitable.