exactly an that note:
Melody was ever meant as a story of a girl, making through to get her career as a professional singer.
The sexual content was a wanted side effect of course.
Melody was never meant to tell a story of a girl who makes all possible sexual experiences (neither normal ones, nor incest or any others) and "nearby" get a singer. So from virgin to incest a 3-some is really not "feeling right" for that story imho.
Once again:
MrDots Melody is a STORY with sexual content, and NOT like a porn, just sexual content of each kind wrapped by something like a story!
And for those who still don't agree or don't like this fact: their fault - i don't care... It's like buying a bottle of beer and complaining for not get drunk by telling that you could get drunk by a bottle of whisky, because both contain alcohol (hope you get, what i mean

)