Stacking videos Swagbucks News/Tips

I have read you shouldn't stack content, but what exactly does that mean?

I know I can do videos through the app on my phone at the same time I do nCraves. But can I also be doing nGages?

What about Watch video playlists and nCraves at the same time? And then throw in videos on the phone?

I don't want to cross any lines. I just am trying to maximize what I can safely do.