It is definitely Season 2, Episode 20: prom queen
Every single episode. That is somewhat of a stupid question. He is in the glee club. He must sing. lolz. :)
The Glee Episode In Which Finn Happens To Sing Jesse's Girl To Rachel Is Laryngitis
They sang it on the episode called On My Way
Episode 4
no
Special Education
Dream On.
like every...
episode 3 "Acafellas"
Season 2 Episode 15: "Sexy"
They are doing "Sing" in Season 2 Episode 13-Comeback
In the power of Madonna episode