well, I guess chisaki and the black haired girl are next to experience the multi-phase Ueno based sexual therapy now that tsubumi and kanako are done with the phase 1 of it.
nice...! this peak knowledge that you had posted shall be made as a case study for future generations. So, I would very much try to transfer it to my offspring once I got to settle with my own family in the future...hopefully...UwU
finally, its a good thing that the bullying past is being addressed by the author vis-a-vis with ueno and tsubomi here...also, hopefully this would led to at least a healthier relationship later on with a bit of recovery.