Niche tube. It's been at the top of the SERP for it's main terms for years.
https://gfy.com/showthread.php?t=1125975
The owner tried to sell it late last year and claimed to make only about $5,000 for the year from it. About 30k daily visits.
Selling it in part it seems because the revenue no longer covers expenses.
I'm not posting this to call anyone out but because I saw that site before and would have figured it made much more given the google traffic it had and that it was fetish. I guess it goes to show that a lot of money really did leave the industry.