Incest in My Canon?

So, anyone who pays any attention at all to Supernatural canon or fandom knows that incest is part of the package deal. We get an awesome soundtrack, a kick-ass car, supernatural bad guys, and incestuous (or vaguely incestuous) heroes. It's all good. It's why we're here. (Actually, I'm mostly here because of the music and the car, but the mythology and the incest keep cropping up.)

( Cut for Spoilers, Length, Sex, Squick, and Thoughts )