"Dlovers" is likely a typo or a mishearing. The correct term in Japanese is "D'lovers" or "D-LOVERS", but given the context, it might refer to a game. "Nishimaki Tohru" is a creator known for visual novels. "Mai innyuuden best" sounds like "My Innocent Days Best" if we transliterate from Japanese. So putting that together, the user is probably referring to the visual novel "D-LOVERS: Mai no Ingyūdetsu Best", which is a compilation of Mai's route from the original D-LOVERS game by Nishimaki Tohru.