I used to have this in my collection of yaoi, but I think I must have deleted it by accident because I can't find it anymore. All I remember about it was that it was set in a country where there were people who 'received' energy, and people who 'transferred' energy. They would be paired up with either a giver or a receiver in that way. It was necessary for both sides to do this energy transfer, because you could die from either having not enough energy or too much energy. They transferred energy through kissing.

It was a rather sweet manga, including a student exchange that one boy of the main couple underwent, going to another country where they didn't have this practice. Wonder if anyone can help me identify the manga? I think the mangaka's name began with B.

Shinkuu Yuusetsu?

That's the one! Thank you 🙂