Both girls are fucked by tentacle monster, idiots still tag it yuri cause girls are on each other while being fucked by tentacles... Please introduce a ffmonster or fftentacle tag for such things than using yuri for whatever trolling reason you think is right.
Nitori whips out a double ended dildo and goes to town on Sanae before making out and suckling her breasts. Sounds like yuri to me. The tentacle monster is having consensual sexual relations with Nitori until she pees in the river on page 16, then it begins to rape her as well.