I saw it on /a/ a while back when I was a newfag to anime.
From what I recall it was a couple about to fuck in a locker during school, and they were trying to not be heard by their classmates who were right outside the locker. I also recall a scenario where the guy's leg brushes in between the chicks thighs and she lets out a small moan. They were both really sweaty too.
>>14154907
The Hentai is i think:
Sora no Iro
Episode 1 at Timeindex 10:35
The Name from your pic:
http://mymangaonline.net/read-online/Skirt-o-Nuida-Sono-Ato-wa-.html
Greetings from Germany