Yes, South Park Season 18 Episode 8 was titled "Cock Magic." But let's get this out of the way because we're a family site and all:
The cock in question referred to chickens, not... you know.
Then again, there was plenty of talk about penises as well on the Comedy Central smash, so read on at your own risk basically.
This South Park episode was less a commentary on some pressing social issue and more an example of creators Trey Parker and Matt Stone pretty much just going crazy. In the most amazing of ways.
The three main topics covered were cockfighting, Magic: The Gathering, and, well, penis magic shows.