You can use more than two songs

There is a way to use more than two songs. It may be a slower process but it works.
Once youre done scratching two songs, u can press the home but, to exit the app. Then, double-tap the home button to see your open apps. Hold the djay app as if you were going to move or delete it, hit the minus button, and then go back into the app to continue djaying.

Phibbsy29 about djay - DJ App & AI Mixer, v1.5