Yes, McCaffrey did mention the issue from time to time - but not nearly as often as one would expect, considering that every green rider, and every rider whose dragon has ever mated with a green dragon, has had hot sweaty man-sex.

Interestingly, her son Todd, who has taken over the franchise, is a lot more comfortable with the implications of sex among riders than McCaffrey herself was.

Many of the other books with human/animal mindbonds (Mercedes Lackey's books, for example) usually hand-wave the sex issue away with some combination of "companion animals are special and don't go into frenzied heat" and "it's possible to tone down the mindbond during mating so the partner who is mating doesn't affect the partner who isn't."

Anyway, I highly recommend Companion to Wolves - aside from the very careful creation of a realistic wolf/human society, it's got a lot to recommend it, especially if you've got a thing for Germanic/Nordic myth.