I will never -- ever -- engage in the style of writing popularized by authors like Joss Whedon, wherein casually knocking off characters is equated with super serious business writing -- I find it deplorable and a massive obstacle to willing suspension of disbelief, not to mention immersion. Treating characters as disposable as tissues is not, in my opinion, good writing at all. Every character is going to be someone's favorite, so killing off any character for good guarantees at least a few readers are going to no longer find your story relatable, and they're going to drop it. And they're justified in doing so. I've never had a problem with a writer bringing characters back, as long as it's not done literally all the time. It's better than having to be afraid of a writer arbitrarily offing the only character you really give a toss about and then pretending they're the most amazing artiste ever by refusing to correct a mistake and bring back a character they never should have done away with in the first place.
I embrace sexuality and nudity too (which, it is worth noting, are not necessarily related at all), and there's a kind of disingenuous obsession with "purity" from some artists that I find fairly contemptible. If it's not your thing, that's fine. But at least don't crap all over other people if they like it; if you haven't done nude studies, as an artist, I personally think that's going to stand in the way of you actually understanding how the body works and even grasp how to put clothes on it, but mileage may vary.
Last but not least: adult content is not pornography. People having sex is not pornography. Pornography is something made expressly for the purpose -- and only for the purpose -- of titillation. No artistic value. No pretense of art. Most often, no story either; it's just sex for the sake of pure titillation. There is nothing wrong with pornography, but people tend to misunderstand what the actual term means.
Explicit sex is not, in and of itself, pornographic. I don't find sex to be tone-disruptive, and I don't even find explicit sex to be that way. I'm perhaps a bit different from most who've spoken up here, in that I don't find the Tapastic terms to be particularly great. But they are a start, in that -- at the very least -- they allow some adult content. Artists shouldn't have to worry about experimentation, and especially with potentially controversial topics or things that might shake things up a bit. Sex is something that, for whatever reason, is like this. Despite most people having sex in their lives, it's still a hot issue! And as such, I think it should be used whenever and wherever any artist feels like playing with it.
That's my two bits, take or leave as you will!