This release is kind of an in-series one, since it pertains to a few of Sanbun Kyoden's other works. Primarily, it deals with Yama Hima no mi Satomi, in which the magazine is actually referenced and submissions were made in-plot.
The basic idea is that this magazine, this being a specific single issue of it, is a submission place for older women who are into being controlled and bondage. Other themes include things like doing these acts while their husbands or children have no clue about it, and that they devote their bodies and lives to their new masters (a common theme found in Sanbun Kyoden works). So this doujinshi is pretty meta. I wish he'd do more like this, and I hope to god that some groups get around to translating it. Most of the fun in NTR manga relates around dialog and situation, not so much the art.
As for the art, Sanbun Kyoden's stuff is fairly plain and repetitive, his women are sometimes indistinguishable from one another. But despite that, he draws a lot of accessories for their clothing, which he always changes up frequently. His backgrounds and shading are usually lacking however.