Stairwell Inspector
1. (noun) slang term for a person (usually who has a significant other already) who has illicit meetings with a sexy co-worker in the building stairwells, for purposes of making-out. An experienced STAIRWELL INSPECTOR will likely have accomplished fully-clothed oral sex sessions, and perhaps even fully clothed doggy-style intercourse on the railing.
Dude is a serious STAIRWELL INSPECTOR! That's the third secretary he's made out with down there this month!