A device made to fuck (or, more precisely, to penetrate repeateadly and mechanically) one person (although there are some machines that can entertain two people at once). Featuring in niche fetish porn, the fucking machine's construction can range from vaguely adapted food processors to converted power tools to entirely custom made contraptions, usually based on electric motors, a driving wheel and shiny chrome piston rods.

Rods, indeed.

From an article by K. Mieszkowski on Salon: Along with the Internet came no shortage of frisky sexual cyborg gadgets, as adventures in teledildonics and Real Dolls prove. Technology would make everything better, even sex.

But post-dot-com blowout, there are no true believers anymore, so, for 2002 we have a tech-sexuality stripped of artifice: machines that fuck. No need to dress up them up with false eyelashes and painted-on lipstick. They're just jittering, gyrating, rotating, rumbling masses of raw thrust.

Fucking machine porn movies (a subset of machine sex, I suppose) usually feature other BDSM elements: among them quite typical to the genre are vacuum devices for nipple stimulation.

See also: Sybian, and the quite impressive www.fuckingmachines.com (Sex at 350 RPM!, sic) website. I cannot resist... The Intruder, The Monster, The Fucksall, The Crane, The Sybian, The Trespasser, The Probe, The Jetaime, The Double Jetaime, The Loving Chair, The Hammer, The Drilldo, The Double Crane, The Goat Milker, The Tit Sucker, The Snake, The Portafuck, The Cathedral, The Toolbox, The Crystal Palace, The Antique Intruder, The Twinserter, The Airstorm, The Lighthouse, The Concrete Vibrator, The Fucking Chair, The Predator, The Reactor, The Chopper, The Hatchet, The Pussy Wacker, The Vulvulator, The Mower, The Soundfucker, The Scorpion, Fuckzilla all look as freaky as they sound.

recently I was pondering if there is any space left for E2, now that Wikipedia is around. And then I realized that E2 can pretty much wack the 'pedia on the smut factor (among other things)