Well that took a long TL note to explain why it's pronounced pong...
WE'RETEAMING UP!Eh?DANGERHAHAHA!CATCH THE PERV!DON'T YOU TRY TO GET AWAY!Oh, how wonderful youth is~EH?!Hold your horses, pardners!
Pong = Southwestern Mandarin pronunciation of 朋 ("peng" in Standard). Spoken in the Hubei/Sichuan/Yunnan/etc. region.
Sometimes used for comedic effect in imitation of Mr. Quin, a video game live streamer with a dog-headed avatar who speaks the same dialect.