Coined by famous short black king streamer Kai Cenat. Also used by lgbtq+ streamer yourragegaming.
It is a version of Gangy, to refer to someone as a close friend, similar to Gangatron, Gangalanch is a step above towards true gangy perfection.
David: Bro whats up with your project? It looks like shit!
Juan: I'm too tired to care.
David: Come on man, you can do everything all tangalanga like that.