So i decided to put all i remember as clear as possible so the uke was a model the seme was a manager or the boss or something like that , in the next chapter he gets jealous over a new model , who is the uke in the next chapter . When the younger model gets his arm broken or maybe leg the owner of the dog or just a guy not sure here again who was an artist i think "helps" him without him even wanting to . There was one more chapter with some other pair and in the end all of the characters were in a hotel with a spa or something like that and when they were doing it everyone was thinking how the others , do it ...
Sorry this is all i remember

Koakuma no Sanctuary ?

a thousand blessings upon you !