The "Flag Code"
-or- United States Code Title 36 Chapter 10
§176. Respect for flag
No disrespect should be shown to the flag of the United States of America; the flag should not be dipped to any person or thing. Regimental colors, .....
(a) ...
(b) ...
(c) ...
(d) The flag should never be used as wearing apparel, bedding, or drapery. It should never be festooned, drawn back, nor up, in folds, but always allowed to fall free. Bunting of blue, white, and red, always arranged .....
~LINK~
http://www.usflag.org/uscode36.html#173