Not sure at all about it being from "Ikusa Otome Valkyrie", but the similarity between the girl in this gif and the one on the other one posted here some time ago decided me to tag it this way.

I think it is, though, it's the first episode if I remember right.

Yes, it's from Ride of the Valkyrie episode 1 about 19 minute.
Plus it's anal.

Personally, I think it was all good with the orcs and the rape up until the dickgirls and the tentacles.