That must be a totally contrived story. The terms "my daughter's friend", "my daughter's girl-friend", and even "my daughter's roommate" have mostly non-sexual meanings when applied to a woman during an introduction.
There really is no need to include the specific intimate details about someone's private life in such a situation. Would anybody ever think of introducing "my son, the masturbator" at lunch, to explain why he didn't bring a date?
