First, let me say that I did a bit of searching and only could find threads on "When is it appropriate to lavalier -person-?"
If I did miss the "What is lavalier?" thread I'm very sorry.
Second, I'm not in a Greek org (yet, hopefully).
Third, what does lavalier mean? I've read a few threads where some fraternity men are asking when they can lavalier their long time girlfriends and a one thread mentioned a young woman saying she wanted her Big to lavalier her. ((Link at bottom))
http://www.greekchat.com/gcforums/showthread.php?t=118219
It's the last post on the second page.