I can play either the master or slave character, more often I play the master because it seems like no one else ever wants to, but given the chance, I also enjoy playing the slave character.
I prefer to write in the third person, past tense, but I can be flexible if necessary.
I do my best to always write a decent-sized post, usually, I average about 3-5 paragraphs but there are exceptions. Occasionally I get carried away and write a mini novel, and other times I fall short. Sometimes things lead to an awkward spot where there's very little a character can do, and I suck at filler/padding so in those situations I have to give a very brief response.
I'm flexible on the plot-to-smut ratio, so long as we don't lose either one completely. I usually try not to go more than 70/30 in either direction, but sometimes I get a bit carried away with one aspect or the other.
I am generally online and able to reply quite regularly, but sometimes I do get busy with other things, or sometimes these upsetting times we live in get me so depressed I can't write, and I might disappear for a while.
Sometimes when I'm away for a while, messages pile up and I forget to reply to someone, if you suspect this may have happened to you feel free to pester me.
I have a thing for playing with furries. If that's a problem I can play humans or various fantasy races, but given the option, I'll almost always play a furry.
I have no preferences when it comes to face claims, we can use whatever kind you prefer or we can just describe our characters.
I sometimes keep weird hours. I have sleep issues that occasionally keep me up all night, so if you see that I've bumped this thread at three in the morning that doesn't necessarily mean I'm in a time zone that might make our schedules incompatible, just that I got tired of tossing and turning and decided to go online.

Basic literacy. I'm no grammar snob, and I make an occasional spelling or grammar mistake myself, but I've met a couple of roleplayers who write like they never finished first grade. I am willing to make allowances for non-native English speakers, (Up to a point, if your English is so shaky we regularly have to ask each what something we wrote meant I'm afraid it won't work out) but if you just never learned to write coherently it's on you to learn not on me to put up with it.
Decent word count. I understand if occasionally there's an awkward spot where you have to write a short post, as I said above I've been there myself, but I've met some roleplayers who will write about four lines of text and consider that a long post, I can't deal with that.
Reasonable pacing. Again I'm not perfect in this area myself, I've been accused of dragging things out or rushing them, so I try to understand when others do this. The thing is I've known people who take the idea of a slow burn to a ridiculous extreme or want to move so quickly that they do two or three timeskips in one post, I can't handle either of these.
Have some idea of what you want, either pick one or more of the plot ideas I have listed below or have plot ideas of your own, don't just ask me to make something new up on the spot, I like brainstorming plots, but we have to have some starting point. And don't ask me to forgo a plot and just jump into some random smut. Smut is great, but there has to be a story to go with it, it doesn't have to be super intricate (although that's good too!), but there has to be a plot.
Communication. If there is anything about the RP you are not satisfied with, pacing, plot-to-smut ratio, kinks getting too extreme, some aspect of the plot you don't like, etcetera, tell me! I'm flexible, we can adjust things if you want. More than once I've had someone dump me because something that could have been fixed had been bugging them for a while and they were too shy to mention it so they just let it fester until it got to a point where they'd rather end the RP altogether.

1. Our characters are the princes of two countries at war, Character A's country is destroying character B's. Character A's father offers Character B's peace, in exchange for Character B becoming Character A's slave.

2. This idea takes place in a strip club/brothel where the strippers/whores are essentially slaves. Character A runs the place, and is a member of a major crime syndicate, that has all but taken over the entire city. Character B is a cop who is sent undercover as a stripper/whore, to get dirt on Character A and the syndicate, but ends up falling for Character A and slowly adapting to life as one of his whores/slaves.

3. This idea is similar to the first, it takes place in a kingdom inhabited by two different species, one of which has been oppressing the other for generations. Character A is the leader of the rebellion, and Character B is the king. Character A is captured but refuses to tell where the rest of the resistance is hiding, he challenges Character B to a wager, for one week Character B will be a slave to Character A, who will try to break him, if Character A fails, he gives up the rest of the resistance, but if he succeeds he becomes the new king and Character B stays his slave forever. Also, I'm thinking that at some point in the past, the positions of the two species were reversed and Character A is secretly the last living descendant of the previous royal family.

4. This one takes place in a world of magic and wizards, and familiars. Except in this world, familiars aren't pets, or demons, or that sort of thing, familiars are slaves with magical aptitude, as in they would have been wizards themselves if they hadn't been slaves. Character A is a young wizard who's just inherited the entire estate of a distant relative, including his exceptionally powerful familiar, Character B. Character B is rather disgruntled about his position as a slave and has long harbored fantasies of turning the tables against his master, but his late master was too powerful, Character A, however, is somewhat less powerful, and becomes an easy target for Character B.

5. This one takes place at a college, where the students on scholarship are slaves to the rich students. Character A is the rich guy, the master. Character B is a poor slave, but until recently he used to be rich until his family lost all their money. I also had an idea maybe they used to be friends as children, then when they got a bit older they started to develop feelings for each other, but it didn't work out because they both saw themselves as doms and after that they kinda became enemies.

6. Character A is the king of a country at war, and losing badly, he seeks help from Character B, a demon, or maybe a morally ambiguous demigod or something, who agrees to help if the king agrees to become his slave.

7. Opposite of the last one, Character A, a demon/demigod/some sort of powerful supernatural being has tyrannized a kingdom for generations until Character B the king finds some ancient magic or something that allows him to restrain Character A's powers and keep him as a slave. The interesting thing about this one is that though the king is the master, prior to the RP he'd have been more or less character A's slave. And his people being used to seeing him in that role would probably struggle with the idea of respecting him, so he'd still sort of be living a dog's life. Also has the potential for a power struggle, like if the king's control over the demon was tied to some sort of object that the demon could steal from him, one of them could be in control one day, the other the next. (Note: I have many possible additional ideas for this plot, but trying to include them all here would turn this into a long rambling mess, send me a message if you'd like to hear more.)

8. This one takes a while to explain. It takes place in a sort of fantasy wild west setting, with magic and maybe some steampunk technology. In this world, there is a town made up entirely of bandits, magically protected so that nobody can see it unless the bandits let them see it. Character A is the big bandit in charge of the town, and he leads a gang made up of his brothers. Years before our story actually begins Character A's youngest brother got tired of taking orders from his brother a ran away, he met Character B and they became partners in crime (and maybe more). But eventually, they had a falling out which ended with the brother being killed. Fast forward a few years Character B has given up crime and become a sheriff or a marshal or whatever (To be honest I'm a bit fuzzy on the difference). Meanwhile, back in the bandit town Character A has been working on a scheme, putting the "empty land" the town is built on up for sale, then robbing and enslaving the people who come looking to buy it. Character B is sent to police the area, and find out exactly what's going on. Character A finds out he's coming and set up an ambush, deciding to get revenge for his brother by enslaving Character B.

9. This one takes place in a corrupt prison where the prisoners regularly molest and abuse each other (in addition to other illicit activities) while the guards either turn a blind eye or actively participate. Enter Character A, the new warden with plans to clean the place up. The guards, not wanting to lose their jobs (not to mention the other possible repercussions) lock him in a cell with Character B, the undisputed toughest inmate in the prison, who proceeds to turn the warden into his new bitch.

(These ideas need some fleshing out, if anyone's interested maybe we can do it together)

10. A superhero is captured and enslaved by a supervillain.

11. CEO with secret submissive fantasies is dominated by his new assistant.

12. A disgruntled genie attempts to turn the tables on his master.