Rodney makes lighters

…or matches, I forget. Rodney is on a world,separated from the team, and he creates some kind of lighter for the townspeople, as part of a local custom. Ronon, Teyla and John come to the planet and almost miss seeing him, but a young boy, who has talked to Rodney before, recognizes Ronon from Rodney's description and he runs after Ronon and the team is reunited. McKay/Sheppard.

FOUND! Matchmaker (duh) by Lavvyan.