The exclaimation made to refer to the powerfull thrusting action during sexual intercourse. Can be shouted anytime to indicate to a fellow chum that you: A)Got laid (in response to an enquiry) B)Would'nt at all mind a session of thrusting the pork steeple into the squish mitten or C) are enquiring whether or not they had a steamy session resulting in the spaffing of precious baby gravy.
Dave: "Hey, how did things go last night?"
Jim: "POW!" (accompanied by single-thrust hip action)
HRH David Schlongtonian-Smyth: "I say old bean, did you get any *POW!* (accompanied by single-thrust hip action) off of Lady Bettingthrop Swollocks?"
Lord Charles Higgingbottom Smedley Jnr: "Myes" (removes pipe, brushes off tweed jacket and nods slowly, yet firmly)