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It is said that friendship between a man and a woman is 100% broken if you go to bed with only a towel on.

"If I cum now... they'll know...!" Even though he desperately tries to keep his voice down while his friend is sleeping... he can't stop the raging pleasure and the sound of the water...!
--The main character, Chiaki, is a dark-skinned student at a boys' school.
He is in love with his bright childhood friend, Ren, but he is depressed because he feels that he is not good enough for her.
Then, four good friends, a boy and a girl, go on a snowboarding trip... Ren is locked out in the hotel corridor with only a towel.
Chiaki, who was passing by, rescues her and takes her to the boys' room, but then her male friend comes back... and she quickly hides under the sheets!
She is almost naked, and there is no way she can stop him...!