This text is shorter, but also relates to the first chapter. If you want to spice up a song that already contains a 7-chord (seventh chord), you can first play the chord without the 7th, and then add it.
In a song in C major, we often see G7, which "wants" to resolve to C. Instead of just playing G7 there, you can use this technique.
So, instead of playing:
[G7]Tra-la-la-la- [C]Laa
you can play:
[G]Tra-la-[G7]la-la [C]Laa.
And in cases where C7 goes to F;
[C7]Tra-la-la-la- [F]Laa.
you can play
[C]Tra-la-[7]la-la- [F]Laa
Our example song now looks like this:
[C]Tra-la-[C7]la-la- [F]Laa.
[G]Tra-la-[G7]la-la- [C]Laa.
So, you play the G chord first, and add the 7th just before changing to the C chord. The same applies to the C chord when it goes to F.
But as with all chord embellishments, it may not always fit. Timing is important, and it might not suit the musical context of that particular song.
How do you know? You'll hear it right away!