Okay -- for those too lazy to look it up the urban dictionary has the following definitions...
"No muff too tough -- An expression used to describe a person's complete lack of discretion in selecting those whom he/she chooses to perform oral sex on."
@Salvage Sailor -- Thank you for sharing part of the SEAL Oath. I never would have imagined.
I haven't seen the movie Lone Survivor, yet, but I just found a short video clip of someone reciting a slightly different variation of the SEAL Oath on YouTube.