After getting settled Alex immediately went to the mixed bathing onsen. On his way he passed Saji, who glared at him with bloody tears as he realized where he was going. He heard from Rias that it was discussed on the way that none of the guys would enter the mixed bath, and there was only their group and that Ren girl so there was no risk of the girls being peeped on. As he was about to enter the changing room he bumped into Grayfia, who had a small tinge of red in her cheeks. Alex had to fight from smiling as he knew she had been drinking.
"Oh Alex, are you going in too?"
"Yes, I decided to go in and enjoy the hot water before the girls enter." She nodded with a small smile on her face, and followed him in. Alex then had the obviously arousing experience of watching the queen of the underworld strip right in front of him. It was especially stimulating to see her crotch had a small crown of silver hair above it. She didn't seem to mind his gaze, and waited for him to undress before going in.
After leaving the changing room they sat down next to each other at a wash station and started scrubbing their bodies. Alex had to admit his eyes went to her tits more than a couple times. While he was enjoying this situation, he was also a little concerned as he didn't know what Grayfia would consider too far. Once they were done with most of their bodies, Grayfia moved behind him and said,
"I'll get your back, then would you get mine after I'm done?" Alex smiled and replied,
"It would be my pleasure." She then took a cloth and started scrubbing his back. He didn't know if it was on purpose or not, but Alex could've sworn he felt a couple hard points brush against his back a few times. Once she was done he moved onto her back, and started admiring her flawless skin. Done with that the two then moved onto getting into the actual water, and started to relax. The two were just enjoying the silence and hot water, until the door opened and an entire crowd of girls came in.
"Alex and big sister?!" Rias said suddenly, while the rest of them behind her stared in shock. Alex sighed and decided to defuse the situation, he recalled that originally at this point Rias and Akeno decided to fight Grayfia and pretty much ruined the trip.
"Hurry up and wash up, the waters nice." Seeing how casual Alex was the girls calmed down, and started to wash themselves. Alex was amazed that beside the ones in the dorms, the Sitri group with Sona and Tsubaki also came in. He grew quite interested with watching each of them washing their bodies, earning several red faces from the Sitri group, before they finally joined him and Grayfia in the onsen.
Ophis copied the rest and washed her body, before simply diving into the water and started swimming in it. Grayfia already took Alex's right side, so Rias took his left, and to everyone's amazement she dragged Sona to take his lap. Sona was so red it wouldn't be strange for someone to think she was about to pass out, as the first time she exposed her body in front of a guy she was made to sit on his naked lap, and felt something poking her butt under her. She immediately tried to stand up and move away, but Alex wrapped his arms around her abdomen, and pulled her closer so that she was leaning against his chest. He then whispered in her ear,
"What's wrong, I'm not going to eat you, yet." She shivered as she heard his words, and the thing under her butt also got bigger and harder. She didn't have anything to worry about though, as Alex was going to wait until he could have her and Serafall before really eating her. That didn't mean he wasn't going to take a few benefits, as he suddenly sealed her mouth with his and started wrestling with her tongue.
Sona gradually got absorbed in the kiss, as Alex moved his hand and started fondling her modest breasts, and used his other one to caress her butt. Even though she put her there, Rias didn't like being left out so she grabbed onto Alex's side and tried to bury it in her breasts. Grayfia then did the same on the other side. So Alex had the queen of the underworld clinging to his right side, the heiress to a noble family on his left, and finally another heiress on his lap being fondled by him, while they were all in the nude.
He then broke the kiss with Sona and moved his mouth to Rias and started wrestling with her tongue. Rias grew absorbed in the kiss, and didn't seem to mind that she was tasting her friends saliva. Contrary to her own expectations, Sona felt a sense of loss when he stopped kissing her, and without her realizing started grinding her butt against the thing below her.
He then stopped caressing Sona with his left hand, and wrapped it around Rias before moving it down until he found her ass, and worked his fingers into her from there. He then did the same with the girl on his right. He was enjoying the feeling enveloping the fingers of both hands, while Sona was grinding on him below. After several minutes of this he broke off the kiss with Rias, and turned to the girl to his right and started a match with her tongue.
Every girl watched as the four people became engrossed in their own world, envious of those involved. Alex continued working the girls to his left and right, while Sona worked on him and herself. This went on for several more minutes before all four reached climax, as Alex felt the sensation on his fingers of both hands tighten, Sona let out a small husky moan, and he felt himself shoot into the water. It wasn't until this point that Alex stopped kissing the girl to his right, and looked into the face of the underworlds queen.
He suddenly felt as if a bucket of cold water was dumped on him. He got into his own rhythm and completely forgot the woman next to him was a married women. A woman married to one of the most powerful people in the underworld and the mother of his child. As she saw the look he had on his face she quickly sobered and thought about what they just did. It didn't take long for to extract herself from his hand and flee the bath. Now that the show was over everyone else also recalled Grayfia's identity, and the situation turned awkward.
Alex soon left the bath and went back to his room more than a little worried about what just happened. He was so distracted that he didn't realize he went a room too far, and walked in on the only other visitor of the inn, who had apparently just left her own private onsen as she was walking around naked. It only took a second for Alex to take in the view of the woman, Ren. Her figure was perfect to say the least, wide hips, large breasts, nice ass. She took one look at him, and immediately turned to hide herself.
"KYYYYYAAAAAAAAAA!"
She cried out as she ran for a towel, giving Alex the perfect view of her ass. He immediately slammed the door closed and went into the right room this time, feeling even worse now than he did a moment before. However as bad as he felt he couldn't help but recall the figure of Ren, and the part that showed how freaky she must be, the heart shaped tattoos on her ass.