[AC Question]

I bought an USB OTG thingy and though my phone reads it, I'm not managing to decently play music directly from it on my music apps. I can play it on Google Play Music, but it only plays one file at a time and also doesn't let me multitask while playing a file. I tried a bunch of different players, none can do it. I also got an app called OTGViewer, but it works by downloading the file to the phone, which kinda kills the reason why I got OTG in first place (saving my short non-expansible internal storage).
My phone is a Nexus 5 running marshmallow, non-rooted.