Sake to Joushi to Amai Kiss

When Momose joined his father's company, he expected to be assigned to a beautiful boss, but in reality, his boss was the dull, old Nishina... One day, after a welcoming party, Momose gets very drunk, so Nishina lets him stay over at his house. After waking up, Momose finds his memories of the previous night to be a blur. Did they do more than just play video games?

(Source: Nihon Bungeisha, translated)