Ah, so that's who Ume is. I was hoping it'd help me figure out who ~maru is, since I can't make out the first kanji of his name. Unfortunately, Umetsu's current site does not appear to have a gallery or blog thing... I guess that's also why this picture has no source url.
Summer is close...It's an ero drawing like I had not done in a whileUme
Umetsu YasuomiShoumaru-kun [1], congratulations on your individual volume! Both of us, let's leave behind works full of indomitable spirit!!
[1] Shoumaru-kun = Shoumaru_(Gadget_Box), AKA Syowmaru.