Stretching your hip flexors can be done at home or at work. Stand with your feet about hip width apart. Make sure you are standing up tall with your toes pointing straight ahead. Put your hands on your hips and step forward with the right foot. Go into a lunge (half-kneeling) position.
Tuck your buttocks under and tilt your pelvis forward. You should feel a mild stretch in the front of your thigh where the hip flexor muscles are located. Hold this stretch 30 seconds and repeat on the other side.
Stretching should be done slowly and gently. Keep the rest of your body (jaw, face, shoulders) loose and relaxed. No bouncing! And don't push to the point of pain or discomfort. You can do more harm than good with these methods. Remember to breathe slowly and naturally. Don't hold your breath while stretching.
Remember advice on-line should not be a substitute for a licensed professional. It's always best to see a licensed physical therapist for stretches specifically designed for your body and your needs.