Drinking human breast milk is enough of a niche fetish that there's even a whole bar in Japan dedicated to it, where men can either buy shots of.
I have breastfed 3 children. Their fathers all tried my milk. Out of curiosity, yes. But also, well I had requested it each time when I was engorged and could not get.
The trend is puzzling experts who say breast milk is meant for human babies, not human grown-ups. They worry about the safety of drinking.