I'm not sure whether or not it was Klaine or CrissColfer, but Kurt/Chris was living in a place like Lima (it could've actually been Lima) and Blaine/Darren had just moved in from San Francisco. He was the "cool" kid, because he floated from group to group and he was also really chill. (Pretty sure pink sunglasses made an appearance.)
Anyway, a bully throws a pee balloon at Kurt/Chris and he's humiliated and then Blaine/Darren pops in and says something insulting to the bully. Kurt/Chris runs out, Blaine/Darren follows after and tells him that his house is nearby so he could change there if he wanted to. Then they became friends, and I think they got together in the end.
Thanks in advance if anyone knows what fic I'm talking about!