Sleeping with Sirens - Roger Rabbit Lyrics Meaning

"So when you have today, you should say all that you have to say..."

This quote of the lyrics is why I like this song. So really, meaning that while you still have today, speak your mind and say everything that you have to say, because you never know when that today is your last. That's what I get from this part.

The rest of the song, I agree with the other.