There was a time Naruto came across Sasuke after his defection from Konoha, during his three years training with Jiraiya. Conveniently, however, he does not remember it due to the fact that he was incredibly drunk.
While Jiraiya was off chasing women, Naruto decided to drown his sorrows in alcohol. And who would guess, at that moment, the reason for his sorrows would sit down beside him?
"Sake," Uchiha Sasuke grunted to the bartender, and Naruto looked at his long-lost friend with his jaw hanging to the floor.
Naruto spent a moment trying to fix his short-circuiting brain, before drunkenly yelling, "You stupid motherfucker!"
The bartender placed the sake in front of Sasuke and he took a sip of it. "Shut up, dobe, nobody wants to hear your obnoxious voice." Sasuke watched with amusement as Naruto turned red with rage.
"No, Sasuke, let me tell you about what nobody wants to hear!" Naruto slurred, while poking Sasuke in the chest. "You whining like the little bitch you are! Oh, my life is so tragic! My brother killed my clan! Pity me! Well let me tell you something, there are more tragic things that could happen! I have a motherfucking monster that just chills out inside me waiting for me to be weak enough so it can fucking destroy everything ever for no apparent reason! Nobody cared about me for twelve years, and I never knew either of my parents! The only friend I had was a fucking nine-tailed demon fox sealed inside me that I didn't even know about until then either!"
Naruto stopped to take a breath, taking in Sasuke's evident rage, before continuing.
"And now, I'm going to fuck you into the ground," he said, and picked Sasuke up by that stupid collar, and dragged him out the door.
Sasuke heard the distant cry of the bartender about the bill not being paid, but was too shocked by the sudden change in Naruto to care. "Isn't this a little rash, dobe?"
"Aren't you a little rash, Sa-suke?" Naruto breathed onto his neck, before slamming him against the wall and claiming his lips.
---
The next morning, Naruto woke alone at the inn. His first thought was "ow," and the second, "…where are my pants?"
When Jiraiya showed up to claim him for training an hour later, he pulled himself together, but couldn't help but wonder what had happened the night before.
---
When Sasuke returned to Orochimaru's lair with a limp and bruises all over his body, Orochimaru couldn't help but ask, "What the hell happened to you?"
Sasuke responded with a kunai through Orochimaru's hand, and stormed off to his room. Orochimaru pulled the blade out with a grimace.
"Sasuke, you bitch! That's the third time this week!"