Tomodachi no Youna Otaku Kouhai to Deisui Ecchi

A story about drinking at home together and ending up having sex with my otaku junior who's like a friend to me. "You and I will never be in that kind of relationship", is what my junior told me. I don't know whether it was because of the alcohol, or her own instinct that she ended up really enjoying herself while having sex with me, but before long she got sober and we found ourselves having some lovey-dovey sex this time. (Source: Melonbooks, translated)