PC is an abbreviation for "private conversion" or "private chat", typically used by
children of primary school
age to indicate that a conversation of
secret, serious, or important nature is about to take place
A PC is usually carried out in a quiet area away from other people's prying ears
"Cocoa, can you come over here with me - I
need to have a PC with you?"
"Why are Alice and
Carla over in that
corner?"
"Oh, don't go over there, they're having a PC."