"Gabe," William said automatically, and then nearly bit his tongue trying to take it back. "Not that I'm insinuating. I mean, you wouldn't have had to... You're right, it's probably not sexually transmitted. Definitely not. The first-years have it, after all. I was just saying... For your entertainment."
That bit of verbal diarrhea over with, he (smoothly) changed the subject. "Tactile or airborne transmission most likely, you think?"