Well, I had some Flexseal tape around, so it went on, and did well for the week in Michigan. However, there's no trip planned in the short term, so I'll look at a more permanent solution.
I'm kind of liking that "Seal-all" product that JFlight linked. It's an MEK and Acetone product, which should chemically weld the plastics together nicely.
(Once I get the previously-applied gunk off the connection.