Otherworld Interspecies Sex ~The Tentacles Return the Favor~

The story of a girl who finds herself lost in another world.
To escape, she employs the help of a jellyfish-like tentacle creature she saved in the past.
It returns her the favor... all the while providing erotic stimulation!

Contains tentacle creature (can communicate), consensual interspecies sex, brain fiddling, indoctrination, parasitism, clothed sex, gapeface / ahegao, cross sections (seX-ray) views, some slight horror-esque elements.

While the tentacle fiddles with the girl's brain, there are no depictions of her disliking the act or being in pain from it. This work has a proper happy end.
As for the horror elements, the other world is a dangerous place for humans, so there are some depictions of other casualties. However, there are no depictions of bleeding.

(Source: DLsite, official)