The only somewhat credible part of the story is the guy resisting by biting the tail. Uncoiling a python is easier if one starts from the tail. The muscles just don't hold as well. In addition. if one grabs the tail near the cloaca and bends upwards, the snake's genitals are put under pressure, and the snake will move to relieve that pressure. Manipulating the direction of movement can help uncoil the snake.