There's a part in it where Kurt takes off his shirt and Blaine sees the bruises from bullying, and kisses his shoulder. Burt comments on this picture at the exhibition. I also remember him asking Blaine if it was really wise for him to do full nude shots somewhere in the fic. They're also all kind of shocked at a picture of Kurt's back with a lot of bruises.
It was pretty fluffy overall, nothing really sexual or angsty about it. I would love if someone could find it for me.
Edit: FOUND! In comments.