I think that your spanish teacher is trying to motivate you to sing (and talk in Spanish). Perhaps watching videos or listening to short, funny stories also may help.
The lyrics are written with "permissions" to break grammar rules, and it can get you a little bit confused.
The best is to have the need to listen and talk in Spanish, practising your grammar skills and improving your vocabulary, "live", with argentinians.
Thanks , yes I agree. But this is more of an exercise I can do when I`m sat in front of the computer or driving and listening to music.