This is the classic on-again, off-again mess, told by the guy who keeps picking up the phone. The hook says it all: "Viene y me repite que me necesita" (She comes and tells me again that she needs me). He knows it's bad for both of them, "Mami, no es sano, esta ida y vuelta" (Babe, it's not healthy, this back and forth), yet "si coincidimos, te miro igual" (if we run into each other, I look at you the same way).
The details are funny and a little sad. She only gets the nerve to call after smoking, "Fuma pa' atreverse a volverme a llamar" (She smokes to work up the courage to call me again), and he answers then hangs up once she starts yelling. Later Justin Quiles tries to end it for good: "Esto no es sano, acabémoslo" (This isn't healthy, let's end it), then immediately spins it as "no es un fin, es un inicio" (it's not an end, it's a beginning). Nobody here is really leaving.
Learner notes: "pa'" is the spoken short form of para (to, in order to), and "mota" is Latin American slang for weed. "Finde" is short for fin de semana (weekend).