Responses
I have a very very vague memory
Is it perhaps "glass syndrome" second couple?
Sadly, no. But thanks for giving me a new manga.
It's yaoi, but it's an old school yaoi where there're multiple stories in this series. This series had a 2 chapter story where, I think, a piano teacher OR tuner (seme) falls in love with the piano student, but due to issues, the student moves in with the seme and they fall in love. The most memorable part, to me, is when the seme asks the uke to join him in to sleep, and the uke has those hilarious wobbly-circled crying eyes (and he's chibi) asking if the bed is too small for the both of them.
The second chapter also contains an extra where the uke's older brother comes back and the uke becomes chibi.