[Locked] Looking for fakku book i read like 6 years ago

There was this Doujin i read like 6 years ago, i remember reading it here on Fakku, It was like there was this one girl whos entrusted with this boy because she needs Sex to live or something along those lines, and all i remember from it is that they had a scene inside of a locker and another one where he uses dumbbells to make a strength training tool for his dick. It was a pretty decently sized story ive been trying to remember this for months and cant find it.