USO

Unit Security Officer: normally the 2IC or Adjutant of a unit who has been jiffed to be responsible for security.

also

The United Service Organizations ... a non profit Spam organisation which is supposed to provide morale, welfare and recreation-type services to the men and women in septic uniform. What it actually means is it ships the Dallas Cowboys cheerleaders all over the world so grunts can have a fly wank.

USO home page here

Dallas Cowboy Cheerleaders page here (remember the tissues)