How do I record audio from the ds capture and my mic at the same time?

[Kaptain_Kernel]

I was on obs and whenever I use my aux cable to record the ds sounds it takes over my mic. I'm not sure how I fix this.

[SuperBeefJerkey]

Knowing how audio devices and OBS work, I have some guesses. What kind of mic is it? If it is a USB mic, I think you need to add multiple audio devices to the OBS capture (I'd have to check that program again to remember exactly what buttons to press). Or, could this be a laptop? Are you referring to a built-in laptop mic? Plugging anything into the mic connector on a laptop will almost certainly override the built-in mic.
As for desktops, you might have two different audio inputs, one is microphone (usually labeled pink) and the other "line-in" (usually labeled blue). If your computer has these, I highly advise that you use "line-in" for the DS audio. It is considered a separate audio device from the microphone.