When former Santa Barbara detective Henry Spencer threatened to deck a "skel" for what he insinuated about Henry's deceased partner, his son Shawn held him back with a soothing "Easy, Sipowicz."
Sure, for us in the Trueniverse, this was a reference to Andy Sipowicz, a NYC detective played by Dennis Franz in the classic crime drama 'NYPD Blue'. However, I'm going to suggest to avoid a Zonk, that Henry and Shawn actually knew this coarse cop.
Of course, there is a major O'Bstacle to this theory - How would a cop and his son from Santa Barbara know a detective in the Big Apple?
That's easy. There must have been a police detective convention held near to Santa Barbara, which would be the only way Henry could justify bringing his little son along.
So as a boy of about ten years of age, Shawn may have been with his father at this cop convention - where he probably got to see this drunken, racist, belligerent detective from New York in action.
Afterwards, I wouldn't be surprised if Henry saw this as an opportunity to impart a life lesson to his son; telling Shawn: "You don't ever want to become that guy."
So when Henry was about to blow his stack twenty years later, Shawn calmed him down by whispering "Easy, Sipowicz."
It was their private code for "Don't become that guy."