Wincest is when you screw around with your
PC. Combination of
Windows, the OS, and incest, since with the amount of time you spend on your computer it's like a family member. You usually get some sort of STD from it, since the virus disabled the firewall.
It includes but is not limited to: adding
RAM, updating drivers, installing new software/hardware, and actually humping the damn thing because you're so lonely.
It is also used to describe awesome incest, but that's a swiftly aging
meme.