A Boys Love and Hentai series worth adding to your list.
The young couple Pico and Chico are out for a date in town when a chance encounter has them immediately seduced by the mysterious runaway named CoCo. Pico is instantly drawn in by CoCo's spiritual outlook and feminine charms, but little does he know that the swaying of his heart will fuel the sparks of jealousy, passion, and desperation between the trio, ready to engulf them in an inferno of arousal and anxiety at any moment. Two may be company, but is three really a crowd?
Plot summary from MyAnimeList. Data and images via Jikan API.