I think it's Angel of Darkness (Injū Kyōshi, 淫獣教師) by Pink Pineapple.Im looking for a hentai series where a professor at a college is a demon or something and he takes his students to hell or another dimension and tey get raped by tentacles. Its not la blue girl. I think the title has something Darkness or something in it.
It's an OVA sequel, why are you looking for it at image galleries?Yeah i found it, very few gifs on gelbooru and some game cg on ehentai. I could probably find more on exhentai if it wasnt for dat damn panda!