Don't Let Your Guard Down Around Young Men!

Sumire is a young woman who often makes mistakes at work and hasn't ever had a boyfriend in all her 25 years of life. She begins to wonder if her day to blossom will ever come. Then the day comes when Hayato, a young man who can speak 5 languages fluently and attends one of the country's most prestigious universities, enters her company as a new part-timer. Hayato ends up helping Sumire out numerous times and all is going well until he finds out… she's a virgin. What's she to do when he leans over her and tells her, "You wanna try it? I'm really good." And to make matters worse, he comes out and tells her that he is going to start living with her. Sumire's life was like a dried up desert but now things are about to get a lot more interesting!

(Source: Manga Reborn)