I came across a guy who licked out my nostrils and ears. It was strangely erotic, not that I felt like returning the favour in kind. And that's coming from someone who likes sticking his nose and tongue into sweaty armpits I do think my immune system has benefitted from all sorts of unusually intimate exposures. When I was younger I'd often get some cold or something much less so these days (I do adhere to safer sex practises).