You can contribute in the Doubles C&C thread, which you can find on the forums home page if you look hard enough, but you might want to lurk in that thread to get a good idea of the meta game/how to write analyses.
As for tours there isn't a seasonal you can join rn but there are the doubles room tour championships as well as some occasional tours like the "girafarig if instead of a line it splits off in a triangular formation" cup.