A device that sucks and vibrates which is hooked up to a box that runs to the printer port on your PC. You pop in a CD-ROM (or, in the future, go to a website) and the device operates based on cues in the "movie" to give you a virtual experience.
Interesting idea, but the software is all proprietary and looks like pretty standard hetero porn. What would be really cool is for someone to reverse engineer the device and put out some open source software that will allow anyone to "reach out and touch someone". Someone could create a touch-sensitive phallus as an input device. A joystick, even...!