NoirMetal, Nobody can full predict the personality of anybody they are reaching out to in first contact messages. This also is assuming you are actually responding to a profile of somebody that is legit to begin with.
Write whatever is on your mind at the time, be authentic about it and own it. Owning it includes accepting whatever response, negative or favorable. If you find you are constantly double thinking and double questioning the type of responses you are making all the time. You are tripping up in your own self doubts about how to not come across sounding like an asshole.
Ironically, some girls love seeing somebody's inner asshole up front right away. Others ones don't and wish to be treated with a high level of respect. All else fails, come across as the polite respectful asshole. Oh hell, just make certain to know which head you are using when responding to a profile. Ironically, in some cases if a sub/slave thinks she/he/it holds too much sexual power or control over things... it's an instant turn off for them. So being all extremely sexual and up in their face about things, may just very well backfire on you.
You might need to mentally desexualize whomever you are responding to, before responding to them. There is no one sure fire way of going about things. If you have to do massive amounts of double thinking about a lot of things, up may end up talking yourself out of having written a killer response and talked yourself into some lame ass response.
One thing to really think about, is that if you are filtering your own true thoughts a lot, you are in a sense not being fully open and honest. It's a bitch. The world is complex like this. So many different personalities to interact with. Everybody having different desires, wants, and all this they are seeking.
Be true to yourself and what you are, Own it, be authentic. Tends to work out best that way. You don't have to try and squeeze into some stereotype of whatever Label you are wearing either. Actually, think about the things which set you apart from those stereotype and roll with it. Think of yourself as a human being responding to another human being on this website.