Well he has a Fallen Angel with him

Screw it, he had already fallen to this point. And as much as Issei would like to keep Asia as innocent as she was, he really wanted to take a bath with a pair of two cute blonds.

Asia blushed as she saw his naked body, and instead of the usually scream he would expect when a male accidentally barged into in the bathroom(at least in the anime), Asia instead turned around and closed her eyes as if she saw something sinful. Even though Issei was pretty sure he managed to get more glimpse of her instead.

"Oh I apologize, I didn't realize you want to take a bath! I will leave-"

" Oh no no, I don't mind, really, in fact, I kinda want you to take a bath with me,"

Issei just blurted out without thinking, this caused the nun to blush more.

"O-oh, really?" Asia stuttered, and he could see her eyes started to swirl.

He mostly placed the Ownership in his house for security and still technically made his parents the "owner", though he could still make or change the rules as long as he stated it.

"Yup, in fact, You and Mittelt are going to be helping me taking a bath as a rule,"

"Is that so? I am sorry that I didn't realize it, I hope I wouldn't be a bother." She turned around and bowed, this made her breast bounced a bit, and Issei took pleasure at observing.

"Sure, in fact, this is a tradition, and we would have a good time," Issei stated, now having two blonds serving in the bath.

"let's turn on the showers."