Tachi mo Dekiru Shiro-kun ni Oshiri Kaihatsu Sareru Hanashi

Yaichi, let me play with your butt! Shiro invites Yaichi over to his place to celebrate his new job. As the drinks start flowing, Shiro suddenly asks if he can give Yaichi a prostate massage. Yaichi's reactions had been so intense the last time they were together that Shiro grew curious about how he'd respond to stimulation back there, too. Still unable to forget his time with Shiro, Yaichi hesitantly agrees, and they start the massage right then and there...

Official Translations:
English: Coolmic, Manga.club, MangaPlaza, Renta!
Others: T.Chinese, Korean