Regarding the meme that part of what is attractive about butches & butchness is the “tension” between femaleness and masculinity: I reject absolutely the idea that femaleness and masculinity are in any kind of opposition and therefore that any such tension exists. In order to assume a contradiction in butch gender, one must first assume an innate connection of femaleness with femininity and maleness with masculinity. This trope is the same old conflation of sex with gender dressed up in queer-positive clothing.
Female masculinity is not a riddle, a paradox or an oxymoron. It is as coherent and straightforward as male masculinity. Any apparent incongruity in butch gender exists is in the eye of the beholder.