Explicit sexual material, and works containing it. Troper discretion is advised.
Some of the works containing this you may have found hidden on the top shelf of your dad's tool shed, under his bed or while surfing on the 'Net. Others may seem like a normal show or book at first, but just when things are getting hot and heavy and you expect a fade to black, you instead get a big surprise - this content has shown up. When you discuss this with your friends expect many nudges, winks, and incredibly lame puns.
Plot, or the lack thereof, is not a requirement. Regardless of medium, these works contain at least one depiction of explicit sex, and most have quite a bit more. Depending on the work in question, It's Not Porn, It's Art may be evoked.
For tropes commonly seen in these types of works, see Sex Tropes.
Obviously, articles with this in it are usually Not Safe for Work.
No examples please - but feel free to mark appropriate works with this category.