Tentacle Monster Mr. Slippery Cums From Behind

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It is rumored that Mr. Slippery is more likely to appear of a rainy day...
Kurage-chan, the protagonist of this story and a normal ol' female student, thought that it was just a silly scary tale... until that fateful day...
That rainy day which we got on a train...
and was assailed from behind by something with countless tentacles.
Stuck in the confined carriage of the train, with nowhere to escape...
the sensuality of her body is raised exponentially...
and she is brought to orgasm over and over again.