Like a lot of my ideas, this is derived from something else I was up to that I was rather enjoying, but ended up getting cut short. Regardless of how that ends... I figured I'd give this a shot. Tentacles are not usually my sort of thing, but I think I could have some fun with them >_>
The scenario: x1 Female has chosen to infiltrate/enter/stumble upon a rather rundown lab. Within it they find very large... Tube things filled with a strange green liquid, and it is bubbling. Now, depending on the female's intent, they may have some sort of show-down with the, surprisingly young, brown haired mad scientist who runs this lab, or perhaps they merely investigate the tube too closely. Suffice to say, the tube contains a sexually curiouos tentacle creature...
Now, that's a bit vague, but that's because I like to leave the other person open to choose what array of... Fetishes or whatever else gets involved in this.
Easily Accomodatable Fetish List: Superheroines, virgins, breasts, pregnancy, loss of innocence, humiliation (No garuntee I'm any good at it, though), helplessness... And quite a few others, I'm sure.
I know it's not a ton to go on, but... Any takers?