I first wrote this scene with Hisagi instead of Iba but then I realized that if he was in school Renji's first year then he had to be too young so I switched him for Iba, but it's a lot harder to get a good hang of Iba's personality. Hope it's ok.
Please don't be to hard on Rangiku for not having stopped drinking-fetal alcohol syndrome wasn't exactly known a hundred years ago, and the way the shinigami seem to operate, they never share any advanced knowledge with the general population, even if it would be beneficial. I'm doing my best to write Soul Society as it's presented, even if it's very odd for a real culture. Seriously, who can even find a group of thirty adults of various ages with absolutely not one in a relationship? Biggest clue ever that Bleach is a kids show in Japan.
Rangiku was sitting across from Ikkaku and Yumichika, of Squad 11 and next to Iba, who had abandoned 11, and was the newly appointed lieutenant of the most mysterious captain in the Gotei, Kamamura of Squad 7. She loved drinking with the men of 11. For most of them drinking was like fighting, an end in itself. She could join them without anyone thinking anything more about it. She really hated it when people thought she was trying to flirt with them, especially when she wasn't.
She raised her sake with a grin and declared, "To moving up in the world!"
A pale hand took hold of her wrist as she brought the cup to her mouth, stopping her inches from her goal.
She twisted to see who had stopped her as the other three raised their eyes.
"Gin?" she declared, surprise and annoyance mingled in her voice. "What are you doing here?"
"What am I-" he leaned down, speaking into her ear, but still loud enough that Iba caught his words. "Hasn't anyone told you what a bad idea it is for you to be drinking now?"
"When did you become such a spoilsport?" Rangiku demanded.
Gin pulled the cup from her hand, ignoring her pout. "Come on, I need to talk to you anyway."
"I don't think so," Rangiku answered. "I don't think I like you today. Iba-kun's ever so much nicer to me. He even offered to pay for my drinks."
Gin's eyes went straight to Iba, who flinched back at the other lieutenant's grin. It looked a little too much like Gin might go for his throat.
"Don't be silly, Ran-chan," Gin said, reaching into his pocket and throwing a few coins on the table. "I'm the only one who buys you drinks."
"Then why did you take it away?" Rangiku demanded, reaching for her sake once more.
"I told you," he said, abruptly lifting her from the raised tatami floor, "I need to talk to you."
"Gin!" she shrieked, throwing her arms around his neck as she found herself being carried through the sakeya.
Yumichika raised an eyebrow, while beside him Ikkaku burst out laughing. "You haven't got a chance!" Ikkaku declared, loudly. "Did you see how she just let him carry her out? No woman would put up with that from anyone she wasn't sleeping with."
Iba frowned at Ikkaku. "Rangiku-san deserves a better man than Ichimaru. I don't know why women are always so blind. She allows him control her entire life. And now he's telling her drinking is bad for her just to stop her from enjoying some time with her friends."
"Bad for her?" Yumichika repeated. "Matsumoto-san drinks more than most women, but not so much that he should be concerned for her health."
"That's what I thought. All he's doing is trying to make her feel bad, telling her it's a bad idea for her to be drinking now," Iba declared, throwing back another cup of sake.
A slow smile spread across Yumichika's face. "Is that what he told her?" he asked.
"Yeah, he decides sake's become bad for her, and she believes him. I don't know what she sees in him."
Yumichika turned around and tapped the woman who sat with her back to him on the shoulder.
The eighth division lieutenant turned around. "Do you boys need something?" Nanao demanded.
"Lieutenant Ise, I have a question for you. What is the number one reason a healthy young woman would abruptly stop drinking?" Yumichika asked her, smiling broadly.
"She's preg-" Nanao broke off, looking over the table. "Where did Rangiku go?"
"Lieutenant Ichimaru came to stop her from drinking," Yumichika told her.
Nanao paled. "You don't think-"
Yumichika shrugged. "Just seemed odd. I know he doesn't drink, but I've never seen him stop her before."
Nanao drew in a deep breath and pushed back her glasses, pulling her calm, professional demeanor back on like a mask. "Well, I think it is quite rude for you to even suggest such a thing," she said, and turned her back on him once more.
Yumichika turned back to Ikkaku and Iba, a smile still on his face. "I'll bet anything you'd like that our dear Matsumoto-san will be Ichimaru-san before the end of the year."
"Poor girl," Iba muttered and didn't bother to pour himself another glass of sake; he drank it directly from the bottle instead.
As soon as they were outside, Gin shunpoed them to a garden near the Tenth Division gate and sat down on a little stone bench beside a still pool. He sat with Rangiku on his lap and brought both of his arms around her, pulling her close and burying his face in her hair. Once again, he whispered, "I'm sorry."
"Gin?" Rangiku said, twisting in his arms, trying to turn to see his face. "Gin, what's wrong? Please, don't. You can't blame yourself for this. I messed up the kido."
His hands went to her face, and he kissed her. He kissed her with everything he had, over and over, holding her close and kissing her.
At first she laughed, kissing him back. She always enjoyed making out in the park, but soon she felt something shift in the way he was kissing her. She could feel desperation and something almost like despair in his kisses.
"Gin," she whispered, pulling back. "Gin, talk to me."
He bowed his forehead to hers, slowly catching his breath. "I've messed up, Ran," he said softly. "I have completely messed everything up, and I'm so sorry."
"Don't," she said, raising a hand to his cheek, trying to raise his head so she could see his face. "This isn't your fault."
"I'm going to protect you, both of you," he promised. "I will." He raised his head and met her eyes. "I will keep both of you safe."
She smiled. "You mean you want the baby?" she asked, hopefully.
"How could I not want your baby?" he answered, letting himself give her a real smile.
"Oh, Gin!" She threw her arms around his neck and pulled him to her. "Everything is going to be perfect!"