Is Natsuyasumi. hentai?
Yes
Rated Rx (Hentai) on MyAnimeList.

ONA · 2013 · 3 episodes · Rx - Hentai
Boys Love, Hentai
Yuu and Natsuki met in the hot sun, during that unforgettable summer vacation... Was it a dream, or...? It was a bittersweet love story? (Source: AniDB)
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