I can't remember much, it may be a oneshot but the seme is a author/writer or just studying at that time and in one scene was forced by the uke's ex to make the seme watch him and the uke do it in front of him. The seme doesn't care, later got annoyed and poked the ex's (beep) with his pencil when he started doing it in front of his face.

Thankyou! (beforhand!)