Put it on over whatever it is you are going to wear riding, ie (body armour, chest protector or maybe just your shirt) the brace should lie comfortably against your shoulders, the front should lie flat on you chest without coming into contact with your mouth when looking down. The back portion will lie relatively flat against your upperback with minimal to no rocking back and forth or side to side. Check out this youtube video for further info. http://www.youtube.com/watch?v=AAIAJfPiFNY