This was great, best I have read in a while (maybe second, after only Yuri Terrorism). I'll be waiting for the sequel with the other pair of sisters being a little bit too curious about what they saw, I'm not a fan of BDSM tho, so I won't third Throbelisk's idea.
I don't think you'll read this, but I just meant that Kawai Rou-sensei started another series without finishing the other one, which will probably be stuck at 10 chapters forever. Don't get me wrong, this one is pretty nice as well, but Gyaru really isn't my favored archetype.
Fortunately, for me anyways, "Scottish Gloria" is not a thing in japanese doujins and fanart, it was funny in the beginning, but I like to understand what I'm reading (I support it if it's with Serena tho).
I don't play JP, but as far as I know, Jane was a friend of "Space Tokiomi", he at some point adopts Space Ishtar, he dies when she was around her teens, then Jane, who pretty much saw her growing, take Space Ishtar into some space adventures (and become bounty hunters). . . something around those lines.
^If I remember correctly, Portugal liked Keijo!!!!!!!! so much that they actually tried to make the sport a reality (with some modifications for safety purposes), if they managed, I don't think so.
Also, I did see one or two japanese videos of it, but I think it was on those TV shows with celebrities and whatnot (I'm sure they have a general name, but I can't remember), so I can't be sure about how serious they were.