I Don't Know Who I Slept With! -My Coworker's Such a Tease!-

"You're already this wet? You're so dirty." After a work party, I wake up in a hotel. I vaguely remember someone calling my name sweetly, giving me all of their love... but he's gone! I must have done it with someone from work! Dazed and confused, I go to my coworker Ryohei for help, but he just laughs at me and says I'm not woman enough! Still, he takes it upon himself to improve my feminine charms, using his tongue and fingers to torture me! It feels so good, just like that night! Is Ryohei the guy...? If not, then who?