Ultimately it comes down to this: There is no need for sex charms explicitly in the game. They only add controversy.
Which isn’t to say that your game can’t include sex charms. But you have to be subtle. Go take a look at SV’s rules for sexual content, and realize that they do not prevent anyone writing stories or doing quests from having sexytimes in their stories. They just have a tasteful fade to black and a bit of allegorical sleight of hand and people will get it.
Humans are humans, and they really really think about sex. There was a thread on the rpg.net forum which was all about the perversion potential of various Charms and powers throughout the Exalted gameline. They had contests. People are going to sex up the gameline. It’s going to happen. People also aren’t dumb. If you do a little verbal double entendre in your Charm mechanics, the audience will understand exactly what you mean. They’re not idiots and you don’t have to treat them like idiots. You don’t have to beat them over the head with “This is the sex Charm! Take this for sexytimes fun!” because they will understand how to use your charms in their games themselves for that. In fact, they will probably do all sorts of things that would make you green just thinking about it.
The important part here is that they get to decide how to use, or not use, the material in a way they are comfortable with. For example; a couple of really good Charms were the Solar Knowing the Soul’s Price and the Dragonblooded Thoughtful Gift Technique. Both of these Charms allowed you to intuit what the target would consider the best possible thing you could give them (the solar version then added in a rider that if you gave them it, you snuck past their MDV or did unnatural influence, I forget what but basically it allowed you to screw them over). In both cases the game never says what the gift in question must be. So if you, in your game, are comfortable with it you could say “Oh yeah, the guild merchant prince looks you up and down, Mr. Appearance 5, Athletics 5, and his interest is obvious.” Then, you know, things could go from there. You could even use the Solar one to play the world’s most effective dom or whatever. But nothing forced you to do so and nobody came out and slapped you in the face with the idea. If you wanted to totally ignore that and keep your gifts and bribes to cunningly designed mechanical nightingales, that is also fine.
By forcing the Charm in question to be about sex and nothing but sex, you are deciding for the game group to deal with the sex issue. Because the Charm exists and the players are going to read it. Even if the decision is “Not at our table, thank you,” it still forces the players to confront the issue and that isn’t an issue everyone is happy confronting. It can lead to player on player acrimony because one player decides perfectly innocently to pick up the sex charm and use it to gather a harem and another player freaks out about it because no discussion happened before the game.
So in conclusion: We aren’t children and don’t need to be treated like them. We can and should decide for ourselves how Charms and sex interact. You can sneak such material into the game through subtlety and innuendo without coming across as prurient or crass and players will see this, and even come up with some entendres you never intended themselves.