Presepada is a fascinating word that literally refers to a nativity scene, but in Brazilian Portuguese, it's commonly used to mean a foolish act, a mess, or a farce.
In this song, Marília Mendonça uses it to scold a man for his irresponsible and hurtful behavior towards his girlfriend. She tells him, "É hora de parar com a presepada" (It's time to stop with the foolishness), highlighting the dramatic and unnecessary trouble he's causing. It's a vivid and culturally specific term that adds a lot of punch to the lyrics.
"Presepada" is a country duet calling out a man who is taking his girlfriend for granted. He is enjoying his early thirties out on the town, nursing hangovers and chasing the next distraction, while she waits up for him at home making plans for their future.
The chorus is a direct challenge, telling him to stop the "presepada" (Brazilian slang for foolish, showing-off behavior) and respect the woman he already has. He is out searching for someone interesting without noticing that she is the brilliant, rare person he claims to want.
By the end, the song asks him to picture her with someone else, driving the point home: appreciate what is right beside him now, because she will not wait forever.