There was an interview with Araki where he denied DIO was bisexual and when questioned why he stayed with Pucci in the same bed, he said something like "well, they were talking a lot and it got really late so really DIO had no choice but to stay in the night" and the interviewer was like "isn't he a vampire" and then Araki recognized that DIO could really be bisexual, as if it was somehow outside of his control