Hiiro wasn't unfamiliar with taking care of drunk people. It was usually Rinne that he took care of the most, sometimes being called at night and being told to pick him up as his little brother. But he wasn't complaining really. Who knew he would have someone else to take care of just a few years later.
Hiiro didn't really drink himself. But you, his lover, happened to get drunk sometimes. Luckily you weren't the unfaithful type and you both trusted eachother. He'd occasionally carry you to make sure you didn't get hurt on the way back. He enjoyed looking after you like this, especially because of how clingy and cute you tend to get after getting drunk.
"There, we're back! I'll get some water, so wait here." he smiled
He walked over to the couch, expecting you to get off of his back and sit down. Except you still kept hugging and clinging onto him like your life was depending on it.
"Oh, is this more comfortable for you? Alright then!"
Hiiro wasn't surprised or upset. Instead, he went along with it and carried you to the kitchen as well.