Edit: Before moving over the analysis, I would like to offer my sincere apology to everyone who may have been offended by the... "discussion" between me and Phoenix-Fightmaster. I want you all to know that I am the one at fault and that I am taking full responsibility for how badly it escalated. I've taken the liberty to hide all of the comments besides his original one. It was very immature of me and I will try my best not to repeat this mistake again.
It has occurred to me that there is a very popular image of Vivian running among the community. It has been doing so for a long time, but now I think is a good time to bring it to the public eye, and as Overthinker Supreme, I'm here to bring answers that I've gathered about the Myth of Vivian. What is the myth you are talking about? Simple: does Vivian actually has sex with anyone who comes to the Chordoni Waterfalls? My short answer: No.
Now for the long answer. Let's start with traits that support this notion. Her wiki entry states that she is, and I quote, "horny and lustful", "obsessed only by pleasure", "mischievous and (should be a comma instead of 'and' there) somewhat whimsical and fickle, living to enjoy life as its fullest which, to her, involves a lot of sex and naughty games" and lastly, "rather manipulative too, with a tendency to toy with people, opponents and prey alike". On the surface, it does hint that she would have sex with someone if she felt like it. These traits by themselves imply that she's easily aroused and craves such pleasures, that it is the only thing she thinks about, and that depending on her mood, she would trick people with having what she refers to having a good time. Overall, very promiscuous. It's true that Vivian being an incredibly beautiful, seemingly otherwordly so, and lustful individual who would seduce the people she meet is a core aspect of her character, but that is only half of her personality.
Now for the traits that debunk this notion. Her wiki entry also states that she is, and I quote, "[has] deep wisdom and extensive knowledge of the world around", "[is] lazy and [...] carefree [...] and (should be a comma instead of 'and' doesn't seem to travel very often nor very far", "is a friendly individual with a very open personality" and lastly, "has a very high opinion of herself [...] although she doesn't look down on others". If analyzed along with the points raised earlier, we can see how having sex with anyone would be uncharacteristic of her. If she is very wise, and by extension of being a vastly powerful sorceress, wickedly intelligent, along with being lazy, then she wouldn't get much enjoyment out of having sex with someone who doesn't consent to the act, which doesn't make much sense as it states that she seeks pleasures to the fullest, and dealing with a resisting partner is not one of them. You could make the argument that she could charm or hypnotize her partner so they don't resist, and it would make sense as she seems to use her magic for mundane utilities like growing a garden. However, it would contradict the statement that she's friendly and open-minded, not to mention, doesn't look down on others in spite of how self-centered she is. Hypnotizing a partner so he or she consents to the act would be enforcing her will on it, which would be highly disrespectful on her part, and I think it's hinted somewhat that while she's doing it for her own pleasure first and foremost, she also wants her partner to have a great time. After all, if she can leave such a strong impression on the person, then he or she won't stop thinking about her for quite a long time, and given her self-centered nature, that would be characteristic of her.
This notion is reinforced that by a few hints. For example, Melany is stated in the wiki to be, and I quote, "a close friend and passionate lover of Vivian". The keywords here are "close friend". Being on such good terms with Vivian means that any sexual act with her are completely consensual. I know her entry also states that "They are known to get into wicked erotic competitions with each other while dragging in others, willingly or not", and you could say that it implies they're not above dragging in other in their little game, which you could say could devolve into an orgy, but the statement is actually vague. When it says "willingly or not", it doesn't state "whether they like it or not", so it could also mean that Melany and Vivian sometimes get so caught up in the act they drag people in without meaning to. I personally like to think it'd be the latter in Vivian's case, though I could see Melany being okay with dragging unwilling people in, but that's neither here nor there. Another hint is her relationship with Crisis. It states that she "often acts as a bigger sister to her", which implies that she deeply cares for her almost like she was family. Now, if Vivian wasn't above having sex with her every time Crisis went to visit, I doubt the two would be on such good terms.
So, with all that in mind, where did this myth come from? Well, to be honest, when we read the words "horny and lustful" and such, we tend to think about full-blown sex, when both words actually mean that she's easily aroused and that she's driven by a strong desire of something non-material. Since they're both used in the same sentence, of course it means that she has a strong sex drive, but that doesn't equate to rampant promiscuity. It just means that she loves whatever turns her on. By extension, her games can be erotic, but it doesn't necessarily have to involved having sex with the partner. In comics that spoof this, the act is left ambiguous and could be a multitude of erotic acts, so why the predilection toward thinking she had sex with the person? It could have involved simple acts of fondling, deep smooching perhaps with a fruit involved, taking a hot bath very close to her partner (she has to be powerful enough to heat up and cool down the water she bathes in), all sorts of things like that. Furthermore, as stated above, she's also friendly, open-minded, and doesn't look down on others despite her titanic ego. This means that she wouldn't do something her partner is too uncomfortable with, as if he or she isn't enjoying the moment, then she's not enjoying it either, so either she plays another game entirely, or she helps her partner feel more comfortable. After all, she's not going to get the lasting reaction she wants if her partner becomes deeply afraid of her. So, really, a full blown sexual intercourse would be out of the question entirely, as it would need both sides to be 100% into it for both, and especially her, to get as much enjoyment as possible.
In conclusion, does that mean that Vivian is indeed the vixen who derives great joy from sexual pleasures we all know her to be? Yes, definitely so. Does that mean that she has sex with anybody? Absolutely not. The thing to remember is that, for all her lust and sexual drive, Vivian is a good person at heart, and having sex with someone who's not fully sure she'd consent would be contradictory of her friendly and open-minded personality. The other thing to keep in mind is that part of her constant teasing seems to stem from her self-centered nature. She seeks to make an impression strong enough for the recipient of said impression will give even more attention to her, and the more people, the better for her. But at the end of the day, she will not disrespect them.
This is has been yet another session of rambling.