Origins unknown; used as a codeword to describe people hooking up; now used as common slang in (mostly the north of) Scotland to describe any kind of sexual activity, and indeed many other activities which have little or nothing to do with sex, and is generally used to indicate that something fortunate has occurred. It can be used as a legitimate verb in regular conversation, but it is normally just shouted, and is accompanied by a hand action where one puts the thumb and middle finger together, and taps them with the index finger.
Chris and Eleanor start making out at a party.

Chris's friends: "PIECING!"

--

Chris and Eleanor start making out in a library or a similarly quiet/awkward situation.

Chris's friends: -hand action-

--

Chris: I got the new Call of Duty!

Chris's friends: "PIECING!" -hand action-

--

Chris: I pieced four girls last night!
by Gregasm November 11, 2009
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similar to bombing (large, elaborate, artistic pieces of graffiti)
by Anonymous August 29, 2003
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The act of possessing a penis; commonly used in conjunction with a description of the size, as in "piecing a twelver"
"Hey, that girl looks hot"

"no way man, thats a dude!"

"are you sure?"

"yeah, I heard he was piecing a niner"
by HorsePuzzle September 3, 2007
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1. A Gun, knife, or other weapon.
2. Anything used for the smoking of various drugs, most commonly marijuana, most commonly a pipe.
3. A graffiti mural.
4. A place.
5. Short - piece of shit.
6. Generic - anything.
1. This piece shoots nice, only cost $50.
2. Dude, nice piece! Let's smoke.
3. Yo, I threw up a hot piece down near 2nd.
4. Dude, I'ma bounce out this piece before drama goes down.
5. Dude, look at that car, what a fucking piece.
6. Yo, nice piece!
by KillerByte August 9, 2004
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Sharing a portion of your cigarette/tobacco/etc.
"Yo lets go stoge."

"Dam I only got one stick left."

"Fuck it den lets just Piece It.
by Sukimonster February 28, 2009
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