Damar drinks it often on Cardassia Prime in season 7, and it seems pretty viscous there.

...dammit, that's a good thought.

There are some drinks that humans like which are more viscous than others. This includes items like port wine and hot chocolate. You also have stews and gravies which use various thickening agents like okra or a roux.

I kind of think that Kanar is like an intoxicating gravy. You know, that might help out with American Thanksgiving.

Kanar has always reminded me of this fruit preserve a friend of mine gave to his pet gecko

It is canonically referred to as disgusting.

Iirc, in later seasons Damar seems to be knocking 'em back with much greater ease on Cardassia Prime than would be possible with the oily stuff seen on DS9.