After the somewhat abstract discussion of shock and horror in games and other media, I thought I would give a few examples of how and why I've used elements of sexuality and the abnormal body in play.
1. The Unfortunate Troglodyte. Some players in my Castle of the Mad Archmage cellar level have come across a chained, pathetic troglodyte with a raw wound between its legs. This sight had more power to shock than I thought it would. The players in question were left disturbed by this seemingly senseless castration.
In fact, the surgery was more of a pragmatic move on the part of some kobolds, who wanted to remove its defensive stench glands and at the same time gain a chemical weapon, glands in a bag.
The point I wanted to make: It's a tough, nasty, competitive world; especially when it comes to this one kobold tribe.
The point my players took away: It's a pointlessly violent, sexually threatening world. Was that a success?
2. Grind Your Bones To Make My Bread. As blogged a long while ago, my first recent campaign kicked off with a horrific plot involving a body-grinding millwheel, whose demonic bone fertilizer created bumper crops. The horror involved evidence of a kidnapped lumberjack, and many others, having fallen victim to the wheel, as well as a number of flaccid half-vegetable Lovecraftian things in the cellars below.
The point I wanted to make: Semi-satire on medieval suspicion of technology and conflation with demons and magic.
The point my players took away: They were very wary and cautious with anything they found in that area, scared of things I'd just put in there as dungeon dressing. The idea of contagious, invisible evil established itself. I think that was a success, transporting the players to a demon-haunted world.
3. Feisty Fiona. An NPC in the current campaign, recurrent by grace of the crazy coincidence roll, is getting a reputation. After the appropriate carousing roll was made, she wound up sleeping with a PC, which I handled in a discreet, three-asterisks manner*. Later, she showed up in a different town with a young "bodyguard" in tow, and loud bangings and moanings were heard from the direction of their inn room.
The point I wanted to make: There are lively characters in this world, memorable and controversial.
The point my players took away: At least one of them was more scandalized by Fiona than I expected. I think they get the point, though.
* I must confess I lack the sexual charisma of an Ed Greenwood to be able to pull that kind of scene off any other way ...
To sum up, knowing the group is key to making these elements come off as intended. And even if they don't, that's not always a bad thing.