Kurenai didn't know about Naru-nii, the prediction of the future, Naruto's training to prevent that, or the absolute secrecy he swore to his future-self he would keep. Kurenai was also unaware of Naruto's dependence on those now forty minutes a day with Naru-nii, when he can talk to someone who cares about him like family, helps and guides like Iruka-sensei, and most importantly, completely believes there's something great in him. Naruto would never reveal that secret to anyone he didn't trust, so he certainly won't be discussing that with her, but that wasn't his only problem.
Kurenai didn't know how sexually conscious Naruto has become. She couldn't see him pondering about training and mastering an area of his young life he or Naru-nii knew very little about. Of course, Ino-chan's words play across his mind like a brass winded instrument blaring in his head, "You don't make me feel good at all!" he recalls Ino yell from beyond the barrier of his front door. And of course,"You don't even know what you're doing!"
Naruto really didn't know what he was doing. Naru-nii couldn't help and some of the books he's looked through are more story based than instructional. Naruto needed an ultimate guide to the female body and how to manipulate it like he does his chakra. He needed a sensei for sex. Kurenai didn't know any of this, but felt a little nudge would move her closer to what she wants. As Naruto ponders whether he should ask—if it's even proper to ask—she challenges his hesitation by inquiring, "do we have a deal? We'll even shake on it so neither one of us backs out of it, okay?"
'She is a woman, and really hot,' Naruto thinks. 'Since she's older, she should know more… unless she's virgin,' Naruto grimaces, then shakes his head. 'A woman this beautiful is probably beating them off with a stick… or kunai,' his mind reminds him. "Well," Naruto hesitantly begins, cheeks turning a tough pink. "There is something I need to learn more about."
"Alright then," Kurenai says with a smile, bringing her index and middle finger up to her chest, as if activating ninjutsu, than extends her paired fingers out in harmony. "On the Konoha honor of reconciliation, we'll promise to help each other out."
Naruto easily recalls the Seal of Reconciliation from Iruka-sensei's classes, but can't help a nagging uncertainty about the differences between each of their needs. "You don't even know what I need help with."
Keeping her hand extended, Kurenai confidently replies, "we're simply agreeing to help each other if it's at all possible. Obviously I won't steal, kill, or abuse someone with jutsu for you. And I can't teach you something if I have no experience with it." Tilting her head with her winning smile, Naruto guardedly joins his paired fingers with hers in amiable harmony.
"Okay than," he agrees, with a firm two-finger shake.
"Good," Kurenai happily states. "I'll see you tomorrow, same time. This is important, so please be there."
"I will," Naruto grumbles.
Moving back to the couches for a celebratory tea, Kurenai asks, "so, what would you like me to help you with?"
Naruto grows incredibly nervous fast, enough so for the beautiful kunoichi to notice. His cheeks grow warm as he looks away from her and scratches his head. "Mnn, haha, well, I uh, ...n- hel… mak- um, gir ls- f-feel-… gd."
Despite his garbled response, Kurenai honed in on the last three words and slowly, very reminiscent of when she attacked him, walks to him. "Uzumaki-kun, I didn't quite catch that. As a self-respecting and very dangerous woman, I suggest you choose your next words wisely."
"...I," he balks a moment at the intensity of her antagonistic red irises, but gritting his teeth, he bravely returns, "I need to learn how to make girls feel good!"
She grabs him by the dirty collar of his jacket and forcefully hoists him up.
"H-hey!"
"Do I look like some sort of harlot to you!?" Kurenai growls. "Put me do-" he tries but she cuts him off. "Or that I would prostitute myself to you for your perverse fantasies?!" He struggles, as he yells, "let go," but she doesn't. "I always knew you weren't very bright, but I never thought you were this stupid!"
"You're choking... me!" She drops him like a sack of potatoes before Naruto angrily whirls on the woman who physically assaulted him for a second time now. "Fine, jeez! You don't want to help me, I get it! Just don't expect me to help you either!"
Taking a deep breath, she practically growls, "we shook!"
"I'm not the one backing out!" he hurls back, rubbing his throat.
"I said I'd help you, but not with that!"
"Fine!" Naruto yells. "It's not like I'm forcing you too. I- I just... don't know a lot about... that, and you said you'd help as long as I don't ask you to kill or steal, or use jutsu on people. And we shook, so, well, that's what I need!" It's silent for a long time, and Naruto mutters, "whatever," before walking to the door.
His hand on the door's knob, he opens the door half way before Kurenai's extended hand slams it closed from behind him, sullenly compromising by countering with, "... I can get you books."
"Oh, wasn't I too stupid for you a minute ago?" he sarcastically asks. "I can't say I've tried all the books but I've read some and they're not- …they don't say what I need to know."
"You're worse than Kakashi," Kurenai mutters exasperatedly. She turns and walks a few paces down the hall before facing him again, pinching the bridge of her nose. "What exactly is it that you're asking?"
"Uh… I can't say exactly what," he slowly struggles to reason aloud. Keeping in honesty of reconciliation, he continues, "it's like I need to learn what to do when I'm with a girl so she doesn't... regret being with me. I want her to feel really good, so- so, if you can show me how to do that, than I'll definitely help you!"
Her analytical mind tries to separate her desire to kill the blond from the ultimate goal. Despite the weight of the choice ahead of her, the mission is Hinata. Naruto's a boy. It's common for young boys to be curious about the female body. Kurenai knows at a planned point in the future, a shinobi-sensei will take his young pupil—if he's single and willing—to Redlight Alley in Konoha or a gambling town in the nation, to properly shed the vestiges of his innocence, but that isn't for several years if she remembers correctly. It's almost unbearable to Kurenai that Uzumaki-kun—the Jinchūriki—would want this of her. 'But the final step is just beyond this,' she thinks. Hinata's fate—the village's next generation—is resting on her shoulders. If she hadn't fucked up maybe she wouldn't be here suffering for it.
"…We're not ever having intercourse," Kurenai phonetically puts down.
Naruto shrugs, completely fine with that stipulation, stating, "as long as I learn what I need to, that's fine."
"Why do you need to know this?" she asks. "You're still so young."
"Why do you need to help Hinata-chan so badly?"
"She's my student," Kurenai easily answers.
"I don't live with Kakashi-sensei," he snaps, clearly pointing out Hinata seems to mean more than her other students.