Engineering, Mechanical engineering, Mechanics, Natural sciences, Physical sciences A solid disk or cylinder that fits inside a hollow cylinder, and moves under pressure (as in an engine) or displaces fluid (as in a pump)
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Entertainment, Lifestyle, Music A valve device in some brass instruments for changing the pitch
The Latino warrior fucked like a man possessed. His lean hips powered the pistoning rod in short, vicious jabs, so rapidly that the shit-streaked cock was a blur as it pounded Captain Randall's butthole, churning the screaming soldier's ass-juices, rectal blood, and smashed turds into a slimy froth.1991, Etienne, “In Enemy Hands”, in Drummer, number 151, page 32: