Sasuke realized he had this thing for Suigetsu, when they were walking together. After he killed Orochimaru when Suigetsu appeared out of his container, He saw that he was naked, Sasuke saw it but then said for him to get some clothes on. So he did. "I've been recuiting new members for this team, and you are the first that I've chosen."
Even though Suigetsu knew about his secret confession AKA love for him, he asked smiling.
"So, are you gonna admit you like me?" Sasuke replied.
"I will, in time."
So they stopped at a restaurant in the Hidden Mist Village and Suigetsu ate yogurt, the maids liked Sasuke because he was cute and all. But Suigetsu defended him because he liked Sasuke back, then shots at them.
"Ladies, this guy is with me!" Then they ran out screaming.
"OMG! Sasuke's gay!!" Then Sasuke and Suigetsu stopped at a cave, it was shut and Suigetsu had Zabuza's sword with him. Sasuke's head turned to Suigetsu and asked.
"Suigetsu, open the door."
"But why can't you use yours?" he asked.
"…because your swords bigger than mine." As Suigetsu blushed he smashed the door open, with the wooden door falling into a heart shape. Then entering, seeing a girl named Karin.
"Why would someone like Sasuke like you? You have glasses a shitty attitude and you're ugly. I have soft smooth skin; I'm handy and useful, plus better looking."
"Have it your way Suigetsu" Karin sighed. So she believed him once Sasuke convinced her that it was the truth. Then they went to sit down, Karin didn't like the fact that Sasuke was in love with him and wanted to straightened Sasuke out. Obviously it didn't work. So Sasuke asked Suigetsu to free the prisoners.
"Why would you choose Suigetsu over me? I mean, he's ugly!" Karin asked angrily but in shock.
"Suigetsu is more useful to me than you are." Sasuke exclaimed. Karin couldn't believe what he heard of what came out of his mouth, it was true. Then Suigetsu grinned to himself as he walked out the door.