You've got two life forms who are hermaphrodites, and they're having sex. But how do you describe it accurately, without calling on human-centric terms like "male" and "female" or "penis" and "vagina"? It's one of those rare writing questions that comes up for both scientists and science fiction writers. In the interests of advancing the state of the art in scientific sex writing, we've got a handy guide to the ins and outs of hermaphrodite sex.
There are a lot of good reasons to describe hermaphrodite sex accurately. You might want to present correct scientific information, as unclouded by human bias as possible. Or you might want to write a science fiction story about hermaphrodite aliens that allows your reader to truly understand what it would mean to have sex without having two sexes. Either way, we've got some pitfalls to avoid and a few pro tips for your next foray into hermaphroditism.