A slang term used by a group of teenagers, representing the process of intercourse. The "P" representing "pussy" another slang term for the vagina. P-time simply means the act of a man(or in odd situations a woman whom happens to have a penis) placing their penis in the vagina, for the age old act of sexual intercourse.
"May i interest you in P-time?"
"I would very much enjoy some P-time right now"
"Yo man....did you?....P-time???"
This is what happens after a Teaching Assistant has decided it just doesn't matter anymore. At this point he or she makes his or her way to the board, exclaims "It's Pee Time" and just unloads.
Student 1: Why does Alosius look all damp?
Student 2: It was P Time in Criminology today.