I've been trying to figure out the best way to use this idea but can't decide on setting or length. The idea is a story ending with a Japanese girl involved in something sexy atoning for her "shamefulness" by committing seppuku (cutting open her belly with a knife and then a second person beheads her). My ideas include:

Porn Industry.
A new debut porn star does a bukkake scene and at the end she apologizes to the camera for all the lewdness she has displayed. She lifts a knife and guts herself while men continue to cum on her, now cumming onto her exposed guts too. Finally she is beheaded with her severed head becoming the cover art. It is described that since honor is so important this is the way all pornos are done, with the female star killing herself at the end to atone for the shame of letting everyone see her naked and being lewd.

Business Meeting.
A young girl's father, a low level employee of the company, has gotten her a job serving the executives tea and refreshments. She is very anxious since any poor performance on her part will reflect on her father as well. The executive's meeting consists of them viewing or partaking in some sort of sexual performance and the girl tries to keep her eyes down but cannot help but meet eyes with one of the pleading sex workers who is the subject/victim of some extreme debauchery. At the end the executives call out her lewdness for watching the sex performance, reveal the knife and other tools for ritual suicide and so she needs to do what it right to protect her family's honor from the shame she has incurred.

Feudal Lord.
Village girl has been chosen to come to castle and be tea server to castle's lord for a month. However she is scared since her first task is to act as the second (the one with the sword) to the previous server who apparently did something very shameful and must now commits an obviously painful seppuku in front of the lord, his wife and their court. The girl serves the lord tea, but soon walks in while he is being serviced by one of the concubines. The girl stares at the lord's penis and the concubine nods for her to come closer and try sucking it herself. Not wanting to upset the lord she complies. Over the month this escalates, with the girl falling in love/lust with the lord and looking forward to each new way he'll fuck her. On the last day of her required service she is lewdly riding the lord when his wife enters and catches them. She is told that she must atone for this shameful act. Later as she lifts a knife to her belly she wonders if this new girl standing behind her with a sword will be able to last a full month without also falling for the lord's charm.