Good luck trying to make any kind of sense from song lyrics. First and easiest way to trip yourself up. Songs never make sense, they're just meant to sound good. Maybe the song has meaning but everyone has their own interpretations. As for your question, I have no idea. I'm inclined to say it's total nonsense.

Learning a language through songs and movies IS a great way! However, you need to know what are GOOD songs and movies. Choose the wrong ones and you learn garbage! Most songs of today are like trash or too slangy, targeting to a specific audience... To answer your question... "Crunch the sky"..., look at these lyrics... could you feel me ? This is standard English, 你想要觸摸我嗎 got a six-pack belly. 因為我有个六塊腹肌! gonna crunch the sky. Getting a six-pack is impossible most of us men, but he was able to do it, so it means that he did the impossible. Hence, he can conquer anything that heaven throws at him. "Do crunches" means "to do sit ups". Haters don't phase me . "phase" is the wrong word. It should be "faze". I got a piece of pie. 我已經有塊 天堂了. "a piece of pie" can also mean "a very easy thing to do". So there are two interpretations from just these lyrics. Context will disambiguate it if the lyricist wanted to be explicit somewhere else. Here's an example of good lyrics... The main song starts at 0:59 https://www.youtube.com/watch?v=P0c3od7KynE

Crunch the sky is not a normal english phrase. Maybe "touch the sky"?

"crunch the sky" sounds like "strike or hit the sky" to me. "a piece of pie" is probably "a piece of work". I'm not sure. Don't overthink this. This is like learning Chinese from Chinese songs. Most of them don't make any sense. Think about 周杰伦‘s songs.