Non-Adult Ideas (but can certainly contain adult scenes):
In a fictional nation / world, the studies of science are forbidden and have been so for generations. The queen who enforces such law uses it to her advantage and owns a few personal scientists. By working together, they rule the land through fright. The people under her reign believe she is capable of very terrifying things simply because they do not understand the science behind her exhibitions and claims. However, there are (of course!) people who break the law and seek knowledge. The story focuses on two scientists who barely escape the raid of their town. The queen's men capture a young female botanist who is special to the two men and proceed in a hunt for the 'criminals'. The two men travel across the land with soldiers on their heels, seeking the truth of a myth about the queen's supposedly dead husband. They strive to raise an army and bring down the queen. (For this story, I'm actually willing to play a few men because it's a novel I've started and never been able to get far with. Either that, or we can edit roles as necessary and one of the scientists can be female. I'm willing to be pretty flexible with this one.)
A woman wakes up from day to day with various parts of her memory in tact. On some days she remembers nothing at all, while on others she can recall vague details. She is travelling with a male companion for whatever reason. Although this is the premise of the plot, it too derives from a novel I've started and never progressed far in. Thus, although I'll state the original intents of the journey and a few other details, be aware that you certainly don't have to abide by them.
In my original plot, the man discovers the woman wondering aimlessly and crying, and suggests she travel with him as a companion. He quickly becomes aware of her situation and vows within himself to take care of her, as she seems very leery of people in general (suggesting at a rough past). His own traveling has been uninspired and simply served as a way to escape the towns that would not accept his views. A very religious man, he believes in a 'god' of fire and in keeping names sacred whenever necessary. In fact, he believes that too many uses of a name causes the fire to consume its owner. His unwillingness to share or use names creates suspicion about his character, and very few people seem to understand his unique religion. After traveling together, the man eventually falls in love with her and dreams of finding a place which will accept them; a place in which they can build a home and cultivate the land. She becomes accustomed to his ideas on a subconscious level, being weary of names even on her bad days. This acute awareness makes her curious about her background and her situation, and she eventually decides that she wants to seek answers. There are more details to the story, but they involve a lot more explanation and the ending of her partner's life. Obviously in our role play, I won' be seeking the end of his life, but the story of their journey and relationship-building.
A wife is abused mentally and physically by her husband. She has no friends and doesn't know how to improve her situation / doesn't value herself enough to seek a way out. She's terribly shy and doesn't dare breathe a word of her situation to anyone. However, one day while running errands for her husband, some incident causes her to stumble into a possible friendship (little does she know it). Basically, she spills some milk or something (doesn't matter), and a sensitive soul (would be your character) notices some bruising. He doesn't say anything about it to give her a sense of security, and strives to slowly develop a relationship with her. He first has to convince her though, that he doesn't want anything outside of friendship, as she'd naturally stray away from befriending any males. This story would be about helping the woman heal and realize she has some value.
Mature Ideas (Probably Smut Oriented, Probably Not Very Original, Few Limits)
In a futuristic setting, society is split between the uber privileged and the not-so-lucky. The world is infatuated with a drug which, unbeknownst to most, creates a sense of apathy and a willingness to accept whatever events / politics take place around it. Those who refuse to incorporate the drug into their lives are seen as little more than street scum and anarchists. Trying to keep her brother out of political trouble, my character gets caught by the police and sent to a huge prison facility. In this fictional world, prisoners are kept in tiny cells surrounding a huge arena where the drugs are grown and cultivated. The prisoners stay in their cells by night, released during the day to collect and prepare the drugs in the open fields. Meeting quotas gains them living essentials. Your character is a prisoner also and had been working to reveal the true nature of the drug. They somehow band together (maybe he protects her or just wants to befriend her) and they develop a plan to escape and fight the drug war.
These will probably only interest role players who enjoy playing as very dominant males who aren't afraid of pushing limits. However, exceptions always exist and I'm willing to edit concepts to suit your fancy if I like your idea. :)
There's nothing spectacular about this idea, so I'm sure someone could offer input to improve the plot. Basically, a young woman works as a teacher and has caught the eye of one of her coworkers. She's shy outside of her profession and doesn't do a lot of socializing with the other teachers. She's also a pushover and everyone knows it. The man that falls for her decides to take advantage and decides to take her one day... maybe in the copier room or whatever (location is not important). He starts with something slightly degrading (maybe anal?), using his strength to dominate her. She actually ends up enjoying it although she'd never admit it, needing a leader in her life. When his suspicions prove to be correct and she doesn't report it, he decides to have her more often, in more rough and degrading ways. (I'd like, but don't require, some watersports in this one.)
For whatever reason, my character is a young woman who has spent most of her life surviving on her own in the woods. Your character comes across her and observes her, noting that she is more animal-like than human. Since he knows that he can train her to do his bidding and face few / no consequences, he decides to take her home. Ideally, he strives to show dominance in every way possible. My only limits are poo and extreme blood / mutilation (I think that'd cover it, but you might surprise me). This means, for example, that he can piss in/on her and even cut her. However, I probably wouldn't be more extreme than that. ((And yes, I'd love for someone to push those limits.))
This rp touches on a very personal experience of mine. I am not wishing to relive the experience, and thus, the plot needs to be written by a very skilled and sensitive author. The situation I went through was not something I'd ever care for or care to repeat, but I do think with modifications, it can become a great BDSM story. That being said, here is my idea with modifications:
A young woman lacking self-confidence marries a man who does little to take care of her or satisfy her needs. (For example, he's very vanilla in bed and does not crave sex often, whereas she has very high libido.) He loves her and is not cruel to her, but she struggles with their relationship because he does behave in a controlling and jealous manner... meaning she can't make friends easily. Having nobody to talk to makes things even more difficult for her, and she desires to make friends. One day, she runs into an old acquaintance whom she met years and years ago, but does not know well. For the past decade or so, they've run into each other maybe twice a year and have had quick and casual conversation. Thus, he knows a little bit about her marriage; he also has a thing for her (physically and somewhat mentally). During this meeting, she decides to try and strike up a friendship with the man, despite her guilty feelings.
They start with a few texts, but the man stays particularly mysterious and passes along 'harmless' flirts. She likes it but tries to ignore it, and eventually opens up to him more and more, in efforts to get more openness from him. In a bad judgement call, she tells him about her fantasies and attraction to dominance, control, and pain. Keeping this in mind, he slowly begins to feed those desires. This could start by her visiting his house (very nervously) a few times just to get some time away from her husband and get work done. He can start with simple commands that involve house chores, then quickly increase his demands. Using her weak state of mind and knowing she'd never be brave enough to tell her husband, this rp can also involve non-con.
A woman with very low self esteem and a strict upbringing is proposed to by your character. She accepts because she believes herself to be in love and never imagined anyone would want to marry her. After dating her and understanding her nature, he knew he could have her any way he wanted. Hiding his domineering and controlling side until their wedding night, he unleashes his darker side and makes her his.
There's nothing too special about this plot. It would focus on a young married couple.... but the husband has an insatiable appetite for sex. Having his way with her while she scrubs the floors, cooks, talks with him, or works on stuff from home... he'd be all over her. His excessive desires also create the need for him to 'feed' her his cum, whether she sucks him off for just breakfast, or all three meals. Heck, if you want to be really unrealistic, I suppose cum could be a staple to her diet / the main thing she consumes.
This plot isn't -completely- smut, though. They'd have conversations about their days and interact like normal couples. She enjoys their relationship and her special little meals.