Google translate says the title is Horny Tentacles, which seems legit.

http://www.dlsite.com/maniax/work/=/product_id/RJ119822.html

Why is Patchouli a magnet for tentacles in hentai?

@User00: Also, why is Alice a target for stalkers, and weirdos in hentai?

Why is Marisa a candidate for sugary sweet yuri in hentai?

Why is Sanae depicted as a slut in most hentai?

Why is Satori considered the perfect loli in hentai?

Why does Kagerou provides a hairy fetish for every hentai artist out there?

Why does Raiko gets her ass spanked every time in hentai?

Why does Yuyuko looks so bewitching in most hentai?

Why do the Prismriver Sisters never get in a threesome in most hentai?

Why do you feel so bad for Hatate in most hentai?

Why can't Kokoro make an really nasty ahegao in most hentai?

Why isn't there enough hentai of Mokou?

Why does Yukka look hot in every hentai she's in?

Why is Risen a useless little bunny who's only good for her sex appeal in hentai?

Why is Kanako depicted as a inexperienced virgin in hentai?

Why is Momiji considered everyone's wiafu in hentai?

Why is Wriggle a futanari in most hentai?

Why is Yourihime a rape victim in most hentai?

Why is Letty so fat, and voluptuous in most hentai?

Why is Futo so cute with her hat off in most hentai?

Why is an completely underrated character like Meling, considered to be the hottest girl in Touhou?

Why is Sakuya an obedient, bondage, sex slave in most hentai?

Why is Flandere a target for sugary sweet vanilla in hentai?

Why is Yukari depicted as a genuine freak of nature in hentai?

Why is Yamame depicted as diabolical, yet cool, and seductive in hentai?

Why is Utsuho depicted as a sweet, and innocent girl in hentai?

Why is Youmu always depicted as a flat chested girl, with a petite figure in hentai?

Why is Byakuren look so cute in every hentai she's in?

Why does Suika make drunken sex look almost appealing?

Why is Yuugi so confident in most hentai?

Why does Nitori make weird sex toys in most hentai?

Why does Eirin supply every rapist/ male character in Gensyoko with weird aphrodisiacs, and sleeping drugs in most hentai?

Why do artists insist that Tenshi has a nice ass in hentai?

Why is there never any hentai of Minma?

Why does Shinki made the greatest MILF character in tohuou hentai?

Why is Chen the instant jailbait character in hentai?

Why is Ran the perfect furry character in hentai?

Why Dose Akkyu have the saddest, most heartbreaking doujins in hentai?

Why does every artist give Komachi huge tits?

Why is Rinnosuke a straight pimp in most hentai?

Why does Reimu become the a perfect target for every genre of hentai there is?

Base +7, everinom +11, Zelinko +11, kitsuneko +10, crazymagic +9, s0ulkill8r +30, Hargo +9, prevertedaccount +5

indeed, why is lady patchouli a "magnet for tentacles"?
i am also curious as to why this is.

Base +8

Popularity and attractiveness aside, it's because she's a wizard/magical girl. It's easy to picture her accidentally summoning up some nasty thing or being involved with some lewd beast somehow. She's also pretty weak, frail, and sheltered, which factors into it too.
She just in general has an affinity for tentacles, like Yukari without the powerful, dominating persona.

Base +7, hisoj +9