Aplicar in Portuguese generally means "to apply" in the sense of putting something into practice or dedicating oneself to a task. While it can be used in many contexts, its usage here is particularly interesting.
In the song, Ed Motta sings "Nos aplicar a viver" (Let's apply ourselves to living). This isn't just about existing; it's about actively engaging with life, dedicating oneself to the experience of living, and making the most of the time we have. It's a call to intentional and joyful participation in life, making it a unique and thought-provoking choice for the lyrics.