Originates from the ancient billy, thinking that a prio was another word for a three of a kind, a poker hand. This statement by a young hood was exploited to the max and is now used when a 3 point shot is dropped.
"Just dropped a tasty prio on ure ass!"
(V.) To prioritize.
(N.) A priority.
Guy: So, are we hanging out later?
Guy 2: No, dude, I have to hang out with Lauren.
Guy: I can't believe you're going prio her over me.
Guy 2: Dude, you know you're my real prio.