Adult PC Game: Tail Touch Girl - Final by I 3 BBQ Archive

The
main character, "Yukiya," lives in a remote village with her only relative, her younger brother.
With her well-trained agility, she raised her younger brother solely by hunting.
One day she went hunting and was attacked by a tentacle monster and infected with a parasite

This is a story of a healthy young girl,
struggling to eliminate the monster that infected her body, saving money from her part time job, and being molested by strangers and tentacles alike.​