A reference to a woman's genitalia (indicative of the pink flesh, of course), specifically referring to intercourse or penetration.
Sally: "So what happened with Jake last night?"
Veronica: "He was in the pink, and it was good."
Bill: "You put the cucumber WHERE?"
Tom: "In the pink."
Singular: a California Highway Patrol officer.
Plural: ChiPs - as in the 80's tv show. Erik Estrada played Poncho ("Ponch") & some other dude played his partner, Jon. Quality show.
I was doin' 95 on I-5 yesterday and all of a sudden, I had two CHiPs on my ass.