>>49525756For Melony, I think some sort of kidnapping scenario would work the best where she "adopts" you as her new son with lots of mommydom. The biggest turn-off there would be anything to do with diapers or messing, that's just gross to me.
For Roxanne, I'd like a classroom setting with a lot of loli goddesses like Lana, Iris, Liza etc learning how best to dominate a man. If lolis aren't cool then teens like lasses or protags will do fine as well. After you've proven yourself to be a good subject, then she rewards you with being her chair. I can't think of any specific no-go areas in that situation.
Whatever works along those lines, I'd be happy to see what you come up with.