How to deal appropriately with an inappropriate sexual relationship
Part of the character arc for my main character from Can I conceal an antihero's insanity - and should I? is that she is a sociopath, prepared to do things that normal people would not. Part of her story arc is that while under-age (she's between 14 and 15 years old at the time), she - on her own initiative - engages in prostitution, with a few boys who attend school with her, as well as with an older man, in order to get the funds to obtain a piece of equipment that will prove vital for the later parts of the story. When she has what she wants from these relationships, she ends them, but in the case of one school boy who does not accept that their relationship has ended, and to let the other school boys to whom she was prostituting herself know that the consequences of going against her will will be dire, she reports them to the authorities, accuses them of rape, and they are convicted. In the case of the older man, she reports him to the authorities in order to fend off an accusation that she is a prostitute.
In case it matters, this is occurring in a slightly post-modern-day USA, (in either New York state or New Jersey) less than 5 years in the future, which is recovering from a disastrous alien attack some years before that had significantly disrupted everyday life, though at the time this occurs, things are slowly returning to normal. Laws are pretty much unchanged, at least in this area - engaging in prostitution is still illegal, as is a person over 18 engaging in sexual relations with a person below the age of consent.
However the reality of the situation is that not only did she initiate these relationships, she was sufficiently mature, even though under-age, to enjoy herself.
How do I show the reader that this character not only initiated but enjoyed these relations, and that her accusations of rape were false, even if her relationship with the older man was legally paedophilia - while he should have known better, she initiated the inappropriate relationship.
Since these relationships involve an under-aged girl initiating, engaging in and enjoying sexual relations, in the first case with a boy who is also under-age, and in the second case with a man old enough that he ought to have known better than to have participated, I am somewhat at a loss as to how to portray this. I don't personally condone what any of the characters have done, but I also need to show that my main character deliberately sought out that which she later turned against her clients.
If all the characters were consenting and of legal age, I would just include a sex scene... and elsewhere in the story I have done just that with other adult characters, but how do I show what I need to show in this case?