World of Tentacles Jumpchain

From the introduction: Some worlds are full of horrifying and erotic things. In such worlds there are creatures, perhaps openly known about or perhaps lurking in the shadows, with suspiciously phallic appendages just waiting to plunge them into the unsuspecting. Such creatures may be products of science, ancient leftovers from another age, or demons called onto this plane of existence. Whatever their origin, events conspire to bring such things into all kinds of sexy situations.