Butterfly or Inner Thigh Stretch
This stretch is very helpful as it keeps your upper legs flexible and prevents muscle pulls and strains.
How to: Sit on the ground in a cross-legged position. Instead of crossing your legs, though, place the soles of your feet together, then move your feet out so that the heel of each foot is about two feet away from your body. Place your hands on your knees, then slowly push them towards the ground. For more of a challenge, lean forward as much as you can while you perform this stretch. This exercise will stretch your upper legs, your thighs and your groins. This is very helpful is keeping your upper legs flexible and preventing muscle pulls and strains.
Source: Live Strong