It sounds like you don't like what your grandparents control and cutting is one thing you find you can control. As someone who had a totally freaky controlling parent, I sympathise. The way I found to freedom is to find bits that I could control.
If they're your favourite songs, then it's worth having a copy of the lyrics to take around with you, or keep in your room. Can you copy them out by hand, or print them out? This way, you control where you get to sing. They think they can control your access to porn, and you seem to have proved them wrong. They're currently controlling where you get to sing and vent, and you can prove them wrong again.