It's definitely sexual assault/rape. I can't imagine this fetish is anywhere near as common as you might think, even in asian countries.
The only way some one would be able to engage in this in reality is if every one was actually consenting.
Because of that I'm able to pretty easily disregard it as fantasy and because fantasy isn't reality its significance is pretty minimal to me. I guess maybe it could be a red flag to maybe avoid some one over? But it seems the more I talk to people on the internet the more I think every one is a red flag.