What you need to understand is BDSM is a hobby that sometimes people make into a lifestyle. Sadist and masochist are actual personality traits. Passwords and stuff only exist when practicing BDSM as a hobby. Here it's juG a sadist and a masochist existing and matching each other. Not BDSM play.
I see thank you for explaining that, I never thought that they could personalities just roleplays when it comes to sex.
It is a personality trait that has a sexual consequence too, they are also like that with everything not just sex but every day situations, many have humiliation kink outside of bedroom: like being yelled at at work, slapped around the face on the streets and so on...
I think both characters are manifesting into bdsm rs ? Thus the lack of proper safe word and other etiquette, and idk for some reason I like the story, the last few chapters are only showing the seme pov, hopefully we will see the uke getting over his guilt and maybe either running away or falling for seme