Will require a wall or solid frame. Extend one arm and bend it at the elbow, so that the upper arm is parallel to the floor and the lower arm forms a right angle upwards. Place your forearm against the wall or frame. Twist the body away from the wall while keeping arm there. Hold for desired duration and then repeat on the other arm.
2)
Similar to 1, but straighten arm so that it is all parallel to the floor. Place hand against the frame or wall. That should be the only body part in contact with the wall. Twist body away from the wall while keeping arm there. Hold for desired duration and then repeat on the other arm.
2)
Stand with knees slightly bent and back straight. Interlock fingers behind the back so that palms face towards the body. Lift arms as high as possible behind (can ask another person to raise them up further for a more intense stretch). Stretch should be felt in the shoulders and the chest. Hold for the required duration.