My heroine in this book is definitely the type that would use the word cock ... however it is set in the 15th century, she is not human and I can push the envelope on the time period 'behavioral' constraints somewhat... not sure the terminology would fit the time period.
Leesee --
-- 'Cock' is one of our oldest words for the male sex organ, dating in writing to 1610 and doiubtless in use long before that. This puts 'cock' in the same ballpark as 'penis' and 'phallus'. It is a fine old word and you should have no hesitation adding it to somebody's 1450 vocabulary.
-- You're not writing Chaucerian prose. You're writing contemporary English with maybe a salting of Middle English words to give it flavor. You aren't limited to a 1450s vocabulary, or to words current before 1700, or to words in use before 1920. You can use any words or phases, from 1350 to 1950, so long as they don't jar the reader into noticing that the language 'sounds' modern.
-- 'Manhood' and 'Womanhood' are about bottom of my list of favorite euphemisms in this field.
-- What level of 'heat' do you want for this book? How explicit are you going to be?
It sounds as if you want to be fairly middle-of-the-road, on-the-library-shelf level.
-- If you want library heat levels, you can start at the library. (Yeah, libraries!) Pull down genre books (including non Romances) and thumb through to the sex scenes.
Like Goldilocks, you're going to find some scenes are too hot and some are too cold. But you'll also find well-written sex scenes with exactly the heat level you want to write.
Xerox maybe fifty sex scenes. That's your research material.
Those xerox pages give you the current popular terms for anatomy and action. They'll also be a guide to workarounds that avoid direct mention of anatomy and action.
-- Ask here in Rom/Womens Fiction for suggestions of what books and what scenes to study.
-- Once you locate authors who do sex scenes with the level of heat you want, you can research on line.
> Go to
http://books.google.com/
> Type in author name
> Pick one of her books
> At the book, go to the search box on the left column. Try plugging in shaft, thrust, cock, breast, hunger, desire or some other words likely to take you to the sex scenes.
-- Finally -- your FMC is not a C15 person. She would not use C15 terminology or think like a human or a C15 human. Her words of actions and anatomies will reflect her background and life experience.
You got yourself a whole set of unique euphemisms. "He was ready as a driver's control rod in a FG230 sports model."