In the song's refrain, there's another example of a common verb used in a secondary sense.
Si dos ya no se llevan bien
"If two don't get along [well]
captions 11, 26, 33 and 39, Jeremías > Uno y uno igual a tres
The first definition you'll probably learn for the common verb llevar is "to carry." Learn the nuances of this versatile verb and you'll find this construction:
Llevarse bien/mal con alguien
"To get on well/badly with somebody"
For more examples -- and more nuances of llevar -- you could check out:
About.com > Spanish language > Using llevar