From Good Girls Scan BL:

Eijun, an up-and-coming calligraphy artist, has had one sided feelings for his childhood friend Kouki, who is a flower arrangement practitioner, for 7 years. Ever since becoming aware of his romantic feelings in high school, he hasn't been able to properly talk to him. But one night, Eijun was invited by Kouki to drink at home. Elated, he confesses his feelings to Kouki after getting himself dead drunk. Despite thinking he’d be rejected by Kouki, Kouki actually gets turned on instead. He tells Eijun, who has grown confused between pleasure and doubt, "I'll put it in here next."