Nureyev inspired sex in his audiences, so people are really interested to note that the panther-like, sexual stage persona -- as opposed to a strictly virile one, like Vasiliev -- didn't transfer to real life. That was in great contrast to Baryshnikov.
I don't understand this at all, unless it has to do with these biographies which I haven't read. How didn't it 'transfer to real life'? How it was shaped and executed and was maybe extremely neurotic is one thing--and in its fashionable promiscuity it does surely fit most definitions of that term after the 70s, when it was still being accommodated and even envied in various vacuous ways--but there was certainly a lot of energy behind it, making it virile. That he had specific tastes and took 'sexual roles not smiled upon by sexual establishments going back to the ancient Greeks' doesn't really change that hyper-enthusiasm and somewhat out-of-control libido, does it? He is well-known to have 'choreographed' and directed many of the episodes, excluding much of the usual spontaneity.
As for 'importance of whether the sex was mechanical', it's just as important as any other aspect of the personality that one can get one's hands on. Otherwise, don't focus on the person him/herself, but only on the work. If there is more, it's all fair game at this point, whether or not tasteless (which is up to the discretion of the researcher and/or writer.) There are a few dancers even lesser-known to the general public than Farrell, Fracci and Alonso, about whose sex lives I know something--but don't know all of it. I'd like to (mildly), but will not feel deprived if I don't know it, and don't imagine I'll be running into the people who might know the answer. Actually, there are some here, but I'd never ask them, and imagine the bf's one description made me by the person--'he's Czech'--most likely answered the question satisfactorily enough for me to decide that this is a probability that I may mention to my best friends only.
Of the ones mentioned, I've never thought of their sex lives much, although have wondered why, if Paul Mejia was such an important figure in the early 70s soap opera, why he and Farrell divorced. I don't know whether this is top-secret material, nor whether it would appear in an upcoming book that someone mentioned (I doubt it. I don't recall that her book even mentioned what ultimately happened to her father, but it may have.) I thought the sex episodes I read in 'Dancing on my Grave' were of minor interest, and that Gelsey was right to refer to them as 'Modern Romance', in an amusing reference to the old magazine.
Sex is definitely the 'other bottom line', so that people either keep it concealed or people find out--whether it's in a book or not doesn't much matter, as far as I am concerned. At least in Nureyev's case, because his was hardly a big secret, nor did he want it to be.