I had no problem googling 'itch io ntr nsfw' and finding this game... But Itch's built in search function is very broken.
Less broken than ill explained. There are two search boxes and the one titled search does not search tags and arbitrarily cuts off results and weighs the results somehow; for instance you cannot find this game with the search term death.
But in these tag combinations there are only like 50-70 games (nsfw is less common)
https://itch.io/games/tag-nsfw/tag-ntr
https://itch.io/games/tag-adult/tag-ntr
For that matter ntr alone has only 90 games. Many devs do not know that they can tag anything. But fetishes are not tagged most of the time anyways.