OVA Yuugao

Every night, Tomoe Hyodai grapples with disturbing nightmares involving steamy encounters with a portly, libidinous student in her office. Gagging at the suggestive glances of her students, she can't help but feel a burning loathe for their lewd behavior. Fatefully stumbling upon Nemoto, the very man who bedded her in her restless slumber, her disdain evaporates into sheer exhilaration as they're thrown together... As a consequence of vowing to obliterate an X-rated video featuring her sister, Mizuki is ruthlessly exploited by Tanabe for two days. Even though the tablets he provides are ostensibly contraceptive pills, they only intensify her yearning. Her illicit trysts with Tanabe continue until one fateful day when she's escorted to a VIP lounge - a shocking tableau awaits her there: a cohort of female students from her school engaged in an orgiastic frenzy with a multitude of men. Worst yet, her cherished sister Aika is among the salacious participants...