This is a really nice story. Two very human characters, each dealing with their own issues and being able to find solace in each other.
I like how despite the theme of bdsm, there's no "rape". Aoki is consensual to the sex, and he treats tengoku normally outside their sex play. Even tengoku is really sadistic only whereas sexual play is involved.
It's refreshingly mature in its storytelling, and in the portrayal of two adult human beings dealing with past trauma. Aoki is not the typical submissive and weak uke, and tengoku is not your average Sadistic and manipulative Seme. 10/10, great story