Takashi act like that because Riku still high schooler. Dating high schooler when you're a grown-up is committed as a crime.
Then should not asking him out in the first place ( ̄へ ̄)
I honestly think that's what's going through his mind right now, but still. He's lead Riku on from the start and continued to flirt. Then he ups and 180s when it turns out Riku is interested as well? Uh.
Takashi act like that because Riku still high schooler. Dating high schooler when you're a grown-up is committed as a crime.