What's this BL manhwa that was popular in 2015 or so?

All I remember about it is that it was black and white. Had TONS of chapters. So much smut.

Pretty sure it was about two besties that liked each other a lot and they're probably neighbors, too. I remember this one scene where one of them climbs on the other's balcony by going onto their own then going around this divider? They probably talked through this divider as well.

The art style (of the MCs at least) is rounder and softer than what I've found online so far. At least one or both of them is blonde.