It should be made clear that Team Jiraiya (also known in various circles as Team Awesome, Team Asshole, and, in very limited circles, Team Four) had gotten quite good at dealing with their sensei's 'quirks.' Their mouth's no longer dropped open at his fighting style, they always kept their money carefully hidden away and they never accepted, or listened to, any of his lengthy advice about women. All in all, they had survived three years under his tutelage not too much more twisted than they had been at the start. The books, however, were new.
"Sensei," Minato said slowly (much in the same tone one would use on an injured animal you knew could kill you with distressing ease), "I thought you said you were writing a masterpiece on the human condition that would change the world with its deep insights and unparallelled acceptance of the foibles of human nature." Jiraiya felt his the vein in his forehead starting to twitch. That was the problem with geniuses (beyond the unstated fact that they had a worrying tendency to go completely insane), they had annoyingly good memories. Sure, Tsunade could remember every single time he had made an ass out of himself over the last twenty sum years, but Orochimaru remembered everything he said and loved to point any contradictions. Minato was the exact same and, as with Orochimaru, the best thing to throw him off the trail was to obfuscate.
"Are you claiming that this isn't?" He huffed. "I notice you haven't even opened your copy. Really, Minato-kun, judging a book by its cover, for shame. One of the worst things a shinobi can do is to fail to look underneath." Sadly, Minato looked unconvinced, despite this genius rebuttal.
"It says pretty clearly that you have to be eighteen to start looking underneath this cover," Fugaku snorted. Personally unfazed by the warning sticker he had already cheerfully dived into his own copy. "Anyway, the only underneath I see looks a lot like porn."
"With inaccurate illustrations," Hiashi added from where he was crouched behind his rival, peering avidly over Fugaku's shoulder (when offered his own copy he had refused on the grounds that no honorable Hyuuga would ever be caught possessing such trash). "I would ask whether you've never had the opportunity to see an actual woman's breast, but I've seen your 'moves.'"
Fugaku blinked, "But how do you know it's all that inaccurate, I'm pretty sure you said that 'no honorable Hyuuga would degrade his power by using in that manner.'" Jiraiya quickly smashed his fist into the ground, letting the earth tremors to shake apart the heirs of Konoha's two most prominent clans, who were rolling around in the dirt attempting to land a good a good punch (he noted with pride that the book had been set out of harms way).
"Idiots, that's not the type of underneath I was talking about," he waved an arm, "I meant the deeper underneath." His students stared at him. Hiashi dabbed his bleeding nose with his handkerchief (as he had informed his teammates many times, 'no honorable Hyuuga spent their time fighting with their fists, like commoners,' Fugaku had been known to suggest that this was because they sucked at it). Fugaku looked blank. Minato smirked.
"You mean we have to look underneath the underneath?" He suggested.
That was the real worst problem with geniuses, from Jiraiya' perspective, their stupid ability to say what he wanted to say, but make it sound cool.