Okay, forgive me for the unashamedly smutty and pornographic title. The role is as it is described however, with me looking for someone to play the sister (preferably slightly older but this is negotiable) who is very much a girly-girl and one that has a reputation for being very demanding and high maintenance when it comes to relationships. She thinks big and has her sights set high. When she see's something she wants, she has to have it. Once she catches wind of her brother having that special something, he'll learn soon enough that even he is no exception.
I'm not looking for a one-shot with the generic 'catches him in the shower' or 'walks in to find him masturbating' scenario. Maybe her brother is concerned by his 'abnormal' size and books an appointment with his general practitioner, asking his sister to accompany him to the clinic/hospital because he is embarrassed. With her brother not fully explaining what his symptoms are, she would become intrigued and agree to drive him to the medical grounds and wait for his examination to finish. She might then catch sight of the doctor (NPC that one or both of us could play) pleasuring him and this would be where she would discover the truth.
From that point onwards your character would take great delight in teasing mine, with her efforts becoming less subtle by the day. She eventually finds herself to be consumed by cock-lust and becomes convinced that her brother secretly wants her too (and judging from the reactions he gives her he does and with his sister's methods growing more successful in bringing his incestuous thoughts to the surface, he's finding it hard to continue fighting temptation). Maybe she finds out that he is a virgin (some may hate this so again, it is entirely negotiable) and takes great delight in taking his innocence and using her experience to train him up to be her ideal lover. Alternatively, maybe she speaks to her brother's only previous girlfriend and finds out the real reasons why she broke up with him.
Which of course, will only serve to further fuel her illicit desires.
I have a few more ideas about how the plot might develop and this could involve kinkier aspects and public acts, perhaps as the two become more daring as little brother expands his sexual repertoire and begins to develop his own form of dominance in the bedroom, treating his sibling as a willing play thing or fuck doll, the two of them sneaking in rampant and passionate moments of release whenever and wherever they can. Regardless, I am looking for something longer term, multiple scenes in different locations, the two risking getting caught on more than one occasion etc. Anyone who enjoys descriptive roleplaying and character development, who is also capable of articulating the emotional problems that occur from the relationship between the two (this isn't going to be a story littered with just sex scenes after all) then please do get in touch as I would love to discuss ideas and more thorough details.
(We could always change the pairing to (Step-?)Mother/Son if that would be preferred)