Tengu no Shiwaza

The goal of naïve high school student, Midori, is to get rid of his virginity! However, he must unexpectedly spend his last summer vacation of high school at his father's family shrine, ruining his summer plans!! One day, whilst bored at the shrine, he decided to have sex with a tengu mask he found. Things were going great until the magic seal broke, and the real tengu appeared...!!

(Source: Tokuma Shoten, translated)