You can download it here.
I can honestly say that I have never ever ever ever thought of this pairing going well together (shame on me! >_<).
Hisagi is one of my favorite characters in Bleach because he looks cool (his character design) and he has a kickass Zanpakutou (looks as if it was made to "reap life itself") while Yumichika, well I see him as something more like Ikkaku's sidekick. He has his good points by the way. I mean, his loyalty to Kenpachi and all, but for the same reasons I like Hisagi (character design and Zanpakutou) I hate him for it.
In my universe, I usually pair him up with Ikkaku, usually one sided love that would never have its fulfillment (cos he's not gay and he's dense)
So this doujinshi came as a nice surprise, it doesn't have much of a plot, just Hisagi-centric, seeing and thinking about Yumichika but it's got a nice feel to it.
(I love seeing Hisagi get flustered and nervous around him. It's cute!!)
(Oh and I just realized how lucky Gin was.)
I don't know if there are other HisagixYumichika doujins out there, but I'll make sure to look out for more >_<