Akin to the Mafia code of silence, but specific to the stag do. This is the standard cop-out clause that means you don't have to admit to getting your knob polished by a stripper (unless you're unlucky enough to be Bryan McFadden, of course). Also extends to any other aspect of the trip that could cause embarassment to any participant.
"Who shat their bed? I couldn't possibly comment as I am bound by Stagmerta never to speak of that weekend to outsiders."