wdym, that's the best part. And it's not even NTR.
You are disparaging one of the best moments of the entire story (I mean the measuring device). What you refer to is likely something that happens as a result after.
I'm not sure about the manga, I'm on the novel train since it's at 12 volumes and seemingly ends in the next, which is a comfy read in itself. + you don't need to wait ~10 years for it to conclude, if they even get to the end of the story.
I was just put off by the anime having terrible animation (all characters have the same dead fish eyes, despite their expressions being the best part of the manga and LN).