Take your nitpicky definitions elsewhere, we have good dickgirl stuff goin' on here by a damn good artist.

Base +11, shrike13 +10, uklo -7, Raift +8, raspberrycake +7, SigmaXXVII +8

There's no incest. Onee-san's being used as "young lady" here. She's a shemale prostitute and they've never met before.

"Anal Sex with a Dickgirl!" might be a more accurate title.

And it's definitely a good book. <3

Base +17, shrike13 +10, Maximum_Joe +31, alteleric2 +9, youngfolk +17, observer1980 +25, prynic +3, Raift +9

@Dark Mac
Correct, it is not incest and yes it's a shemale prostitute.
You can see the tags from the pixiv account of the artist, http://www.pixiv.net/member_illust.php?mode=medium&illust_id=30124218

Base +8, Maximum_Joe +31, alteleric2 +9, marthsyn +8, Luna_Flina +20

Wow! I didn't expect to see this so soon, thanks. Now to get the two new packs from Yokoyama Lynch (if I could really dream, I'd like to see the doujin version of those too).

One sour note: The artist posted a rough sketch of the girl slamming the guy's ass from behind, but it didn't get included here. You can view this on the artist's homepage (not Pixiv).

Tagging protip: If somebody wanted to use the artist's Pixiv account directory name, it's nokoppa, with two Ps, not "nokopa."

And here I am stuck with a +5 base bonus, pissin' in the wind.

Base +5, marthsyn +8, dawatched +9, vicel +9, SigmaXXVII +8