Thanks for writing for me! I'm very excited about this exchange, and I hope some of the following letter is helpful, but optional details are definitely optional. Ignore the whole thing beyond the pairings/kinks we've matched on if you want. Anything that fits those I'll be delighted to read.
Likes for Fic
I'm totally up for PWP, but if you're looking to put plot in, that's cool too. I'm definitely always up for characters snatching moments for sex in the middle of adventures, or celebrating at the end of them, and I have a fondness for time travel/parallel universes (canon divergent variety)/etc. tropes in particular. I'm very happy with all sorts of formats, including first/second person as well as third, present tense as well as past, epistolatory fic, etc. For kinks with a power differential, I have a very slight preference for the sub's point of view, but only a very slight one. In general, I like people having fun while they're having sex; it definitely doesn't have to be all serious all the time. Things going slightly wrong for comic effect is definitely good.
Likes for Art
I like art that portrays some particular moment, either before, during or after, and implies what's happened/going to happen. (On the "after" side of things, I do like characters looking as though they've very thoroughly enjoyed themselves.) I am particularly fond of characters looking at each other in meaningful ways.
General likes
There are an awful lot of kinks in the tag set I like the look of but have not necessarily included for all fandoms/pairings because I'm trying to keep my requests relatively manageable. So here is a (non-exhaustive) list of kinks that caught my eye; adding any of these to your fic is very likely to make me happy. (You may notice a few themes ...)
Awkward Sex; BDSM; Blow Jobs; Body Worship; Bondage; Boot Worship; Breast Fucking; Breast Worship; Caning; Chains; Clothed/Naked; Cock Worship; Collars; Competence Kink; Corsetry; Crossdressing; Cunnilingus; Dildos; Dirty Talk; Doggy Style; Dom/sub; Femdom; Femsub; Handcuffs; Het Anal; High Heels; Historical Roleplay; Light Bondage; Light Dom/sub; Lingerie; Nipple Clamps; Obedience; Open Relationships; orgasm control/edging; Orgy; Pegging; Phone Sex; Pussy Worship; Roleplay; Rough Sex; Semi-Public Sex; Sex in Virtual Reality; Sex Toys; Sex Toys Under Clothing; Sharing Fantasies; Spanking; Spitroasting; Spreader Bars; Strap-Ons; Strip Tease; Stripping; Subdrop/Topdrop; Submission; Switching; Telepathic Sex; Uniform Kink; Whipping; Woman on Top; Worship; Xeno
DNWs
My major DNWs are major character death, rape/noncon and underage. (NB in any situations where there is the possibility of doubt, I don't consider my requested pairings to constitute underage, obviously.) Since those are all archive warnings and I left them unticked (along with CNTW) on the signup form, there shouldn't be too much ambiguity there. Other than that my main requests would be for you to avoid AUs (other than the canon divergent kind) and watersports/scat/bloodplay/emetophilia, which again are kinks I haven't requested.
My specific requests
There's a lot of iddy headcanon stuff here that I strongly urge you to take or leave as it suits you, optional details being optional and all.
Doctor Who: Jenny/Vastra
Requested kinks for this pairing: BDSM, Caning, Competence Kink, Dom/sub, Femdom, Femsub, Spanking, Whipping
I see Vastra as the top, though I could be persuaded that they switch at times. I can see the competence kink working in both directions, too, but I mostly perceive it as Jenny liking watching Vastra do detecting. (I do have an idea that Vastra is more likely to be into a heavy scene while she's busy mulling over a case -- kind of her equivalent of a four-pipe problem -- and so Jenny deliberately goes out looking for work for them as a consequence.)
Doctor Who: Ace/Gwendoline
Requested kinks for this pairing: Corsetry, Clothed/Naked, Crossdressing, Historical Roleplay
Is it really "Historical Roleplay" if it's actually going-and-visiting history? But you get the idea. The other kinks should be fairly self-explanatory given canon. I would be equally happy with something set during Ghost Light, or some sort of Gwendoline-on-the-TARDIS AU if you want.
Doctor Who: Ten/River, Eleven/River, Twelve/River
Requested kinks for this pairing: Femdom, Femsub, Het Anal, Light bondage, Open relationships, Pegging, Spanking, Strap-Ons, Submission, Switching
I definitely see these two as poly switches who are into a wide range of things, though probably with River being the one to introduce new ideas. Anything exploring that sort of dynamic would be good. I'm quite into the idea of their out-of-order meeting leading to one of them doing something they know the other likes from past experience, but it turns out to be the first time from their point of view.
Fantastic Four (comics): Susan/Reed
Requested kinks for this pairing: Sex where one person is invisible, Shapeshifting, Switching, Uniform Kink
OK, so I did nominate this pairing pretty much entirely so I could request the invisible sex once I'd seen it in the tag set, but that doesn't mean I wouldn't be into the others too! (I'm possibly stretching a point here by calling Reed's abilities "Shapeshifting" but that's what I'm referring to there.) I definitely see them as switches (I think both of them in their own way could at times do with relaxing by letting the other take charge). On the "uniform kink" end, I would be up for an explanation of why they keep changing costumes recently, or something to do with unstable molecules ...
DS9: Kira/Odo
Requested kinks for this pairing: Bondage, Light Bondage, Shapeshifting, Worship
Something involving Odo's abilities would be great, whether that's him in liquid form, him impersonating someone else (one of their station colleagues? Kira herself for selfcest purposes? Double bonus points if it's Mirror!Kira for the purposes of Kira trying to work out her own feelings). Bondage wise I'm envisaged Odo using himself to restrain Kira, if that makes sense, but "how could you tie up a shapeshifter?" is definitely an interesting question. The Worship I definitely see as Odo->Kira given the overall nature of their relationship.
TNG: Picard/Crusher
Requested kinks for this pairing: Bets & Wagers, Historical Roleplay, Medical Kink, Sex in Virtual Reality
I am in love with the angsty backstory of these two about Jack and so on, but while you should feel free to include a bit of that if you want, I'm leaning more towards them letting their hair down (OK, Bev letting her hair down) and having some fun with these prompts. "Bets & Wagers", I'm thinking in terms of the Enterprise-D crew's passion for poker (Picard does join in at the very end of the show!). "Historical Roleplay" and "Sex in Virtual Reality" I'm mostly thinking in holodeck terms. (Dixon Hill, maybe?) On the "Medical Kink" side, I'm sort of thinking of Jean-Luc's reluctance to get his physical, Beverly turning it into a game, that sort of thing.
TNG: Riker/Troi + Riker/Troi/other (including the others specified in the tag set: Ro, Worf, Thomas Riker)
Requested kinks for this pairing: Bets & Wagers, Double Penetration, Open Relationships, Switching, Telepathic Sex
I have a very iddy headcanon for Riker/Troi that their psychic link means they are basically guaranteed simultaneous orgasms ... even if it's not each other they're having sex with. In threesome terms I'm kind of imagining them using this to good effect.
I see them as a very switchy couple: Deanna comes from a matriarchal society and all that, but I can see her exploring her submissive tendencies too. I could particularly see them both dominating the third in a threesome.
WicDiv: all the pairings (literally, I ticked "Any")
Requested kinks: Body Worship, Breast Worship, Cock Worship, Pussy Worship, Worship
OK, so I'm cheating a bit here by using a bunch of "worship" tags for the fandom with all the gods in it, but I would be genuinely happy with anything here from the enormo list of tags up top. I would be happy with something very fucked-up in keeping with the tone of canon, or something cheerier about my faves before everything started to go horribly wrong for them, or something in between.
(Note on Woden: I am actually up for Woden being just as vile as he is canon in the right context, but please don't have the narrative itself supporting his viewpoint unless it's first person.)
TFA: Rey/Jess, Rey/Leia, Rey/Phasma, Rey/female alien
Requested kinks: Awkward Sex, Body Worship, Competence Kink, Cunnilingus, Sharing Fantasies, Telekinetic Sex, Telepathic Sex
Basically: Rey femslash, yes please! Force sex a definite bonus. I'm envisaging the "Awkward Sex" and "Sharing Fantasies" in terms of Rey not having had any outlet for her sexuality in her life on Jakku. The Competence Kink could go in the direction of other characters being amazed by Rey's Jedi abilities, or just as much Rey being in awe of these people who she's never really imagined meeting.
For Rey/Phasma, I would prefer some sort of Phasma defected/was always a secret agent for the Resistance/etc. scenario. Or perhaps a Phasma who's been captured. But please not a loyal-First-Order-Phasma who has the upper hand. (Rey and Undercover Phasma have to maintain the pretence that that's what's going on, on the other hand: awesome.)
KotOR II: Exile/Atris, Exile/Sion, Exile/Handmaiden, Exile/Disciple, Exile/Atton, Kavar/Talia
Requested kinks: Competence Kink, Fight Sex, Loyalty, Telekinetic Sex, Telepathic Sex
For telekinetic and telepathic sex, I'm basically thinking Force Sex, obviously. The "Fight Sex" and "Loyalty" are basically the entire themes of the game, between the learning-through-battle stuff (that particularly applies to Handmaiden, of course) and the force bonds.
I have no preferences on Exile gender for any of the ships involving Exile. Exile/Atris and Exile/Sion, I'd be interested in fairly twisted scenarios for. (Long range Force Sex between Exile and Sion in particular would be intriguing, and what if Atris had decided to keep hold of Exile for some "re-education" on Telos?) I could go for twisted scenarios with the other Exile ships too, in a Dark Side route way (though please no outright noncon -- willing acolytes of a Sith Lord Exile thanks to alignment warping on the other hand is fine).
Oh, and Kavar/Talia are the Anakin/Padme of their era, as far as I'm concerned, only Kavar's got his head a bit better screwed on (it's nicely understated in the game but if you crack the locks on the containers in that bedroom you wander into in the Palace section, there are things that blatantly belong to both of them being stored there ...).