None of these are intended to be fully fleshed out ideas or specific requests for a long term (or even short term) roleplay/story, but they are ideas that I think might be fun to include as part of something else or as a seed for building other ideas around. If any of these ideas (or anything else along a similar theme) sound appealing, just let me know, and we can work on altering them to suit your particular desires as well as mine.
I'll add more of these as I think of them (or run across interesting ideas in other threads), please contact me by IM instead of posting here if you want to expand on any of these.
(Fem seeking Male, slow, mild sci-fi or fantasy elements. Some additional taboo element or risque twist required to keep it interesting.)
Nothing complicated here, just a slow boil sort of scene focusing on longing and trepidation, usually with some sort of obstacle keeping the two partners apart until the time is right. I'd prefer playing the female partner for this one, though I'm flexible enough to consider playing either role (or trying another pairing altogether).
This probably isn't interesting enough on its own to keep me focused, hence the note about including some additional taboo element or twist to make it more intense (Incest, Domination/Submission, mild non-con, exotic/inhuman partners, etc.) Although this idea is a bit more generic (and a lot more tame, even with some added twist) than the rest, I'm including it because I try to work small scenes along these lines in alongside non-adult roleplay in more serious games, and I would be open to the idea of trying it out as the central focus of a medium length roleplay of some sort.
Too Late Now
(Naive/Inexperienced partner seeking anyone, Consensual but with unexpected consequences/slightly non-con)
A scene in which the more naive/young partner (which I would usually prefer to play) gets into a situation they can't get out of easily by accident or agrees to do something they shouldn't have and can't back out, either because they can't bring themselves to back down from their own boasts or because they are physically incapable of escaping. Usually I would prefer if there is some consequence to the scene. It could be as simple as just a frightening experience, a risk of pregnancy, or knowledge they may be blackmailed in the future. or it could go right up the scale to pain during the act, physical harm, or worse.
This scene works particularly well for me if part of the reason the more naive partner is stuck in the situation is the desire or instincts of the other partner making them unwilling to take no for an answer. (For example, an anthro partner who is just overwhelmed once he is in the act, and absolutely cannot bring himself to stop, even if it hurts a bit for the much more petite human girl he is with). This scene completely does not work for me if the controlling partner is doing it for cruel or degrading reasons, so no torture porn or insults and abuse. The motivation has to at least involve honest desire or need (though being mean -and- motivated by desire is fine, as long as it isn't too unbalanced).
The Lost Little Deer
(Trap seeking Man or Woman, NC/Force, Trapdom, usually somewhat rough/extreme)
Sort of the inverse of "Too Late Now" this scene involves a very feminine trap who allows someone to seduce or pursue them under false pretenses then turns the tables on their partner, usually rather roughly. I've run this one a few times before in other venues, and the most common version involves a very, very well hung anthro deer, hence the "Lost little deer" of the title. I'm very flexible on the specifics though, so if fur isn't your thing, I can work around it.
Word of warning, this can get very, very rough (particularly if I'm in character as the deer character), so we should probably talk about your limits some if you want to try this particular fantasy.
(Fem seeking Male monster or exotic, typically non-consensual or mind control)
Nothing too unexpected here, I imagine the title alone is enough for some people to know what this fantasy is. A scene involving a strong female character, adventurer, or explorer who is ambushed/trapped/beaten by a monster/creature/exotic fantasy beast and forced to satisfy it, in one way or another. Such scenes typically end in the female partner (who I would usually like to play) either giving in, going mad, being turned into a mindless slave, or dying from the attempt (hence the term "Bad End") and is really only suitable for a one shot or short roleplay (unless you also wanted to run some sort of redemption/escape/twist ending that allowed it to continue).