For those who are confused, the difference between this and BDSM is consent. Technically you can do sexual play like painplay without consent (that's sexual harassment or assault!), but BDSM as a culture strictly defines itself as safe, sane, consensual. There should never be a "surprise! its a violent dom!" moment in real BDSM, but of course since this is fictional it tends to go more extreme (like how other doujins play off rape with "she liked it in the end" for those who like rapeplay)
For those of you who like painplay irl but are wary of BDSM, believe me, you'd rather have an experienced dom choke you than springing it on a person who doesn't know anything about where and how to hit without leaving lasting marks/actual damage