I recently returned from Nepal, and managed to smuggle a kg of nak cheese with me.
It is glorious and I will miss it so much once my supply is gone. It's a hard cheese, similar to pecorino, and it takes some force to cut it. Keeps well unrefrigerated, thankfully.
The taste is rather mild, although as you eat it it does become a bit sharper. The smell is sharp and musty, much stronger than the taste. I like it, but most of my fellow trekkers didn't like the smell but liked the taste.
OK, you made me look up "nak" and I learned something today.
"The English word "yak" derives from the Tibetan (Tibetan: གཡག་, Wylie: g.yag), or gyag – in Tibetan this refers only to the male of the species, the female being called a dri or nak. In English, as in most other languages which have borrowed the word, "yak" is usually used for both sexes."