Ash already knew not to take flirting advice from Brock, or even Professor Oak. Neither of them gave good advice; Brock in particular because Ash always saw what happened whenever he tried to flirt with a girl, like a Nurse Joy or an Officer Jenny. Long story short, not good.
So flirting with Misty presented some challenges.
Looking at her from across the room in the League function, Ash tugged on his collar, gulped and looked over at Pikachu. The little mouse wondered what the human was thinking. He just rolled his eyes. "Pikapi, Pikachu."
Ash couldn't exactly calm down, he had a mission! To get a date with Misty! "Think I can do it?" he asked.
"Pi-ka!"
"Okay!" he said. He took a swig of his drink and power walked across the room with Pikachu chanting,
"Pi-ka-pi! Pi-ka-pi! Pi-ka-pi!"
Misty did not look up from the sandwich in her lap, so she was surprised when Ash rigidly sat down next to her. "Ash?" she asked with a mouthfull of a ham & cheese sandwich, "You're here too?"
"Haha, um, yeah!" he said. "Nice to see you too!"
"What are you doing?"
"Um, nice night, isn't it?" he asked.
"Ash, what are you doing?"
"I'M FLIRTING WITH YOU!" he blurted out. Pikachu facepalmed from across the room. Yeah, he could hear i t.
Misty rolled her eyes and swallowed her sandwich. "Well you're doing a bad job," she said. Ash hung his head. "But, it's nice to have a friend to talk to."