He appears in the second part of Sensitive Pornograph. He "supposedly" is the rabbit that Ueno is suppose to be "pet-sitting" for. Turns out, Aki is found by Ueno in a closet. This is a very short episode between the two boys. Aki and Ueno are video taped having sex by this mystery man. After Ueno and Aki "do the deed" Ueno leaves and Aki is left alone. Shortly after the mystery man appears and Aki tells him that he doesn't want to be his "pet" any more.
