Raivinha is the diminutive form of raiva (anger). The suffix -inha softens the meaning, implying a 'little anger' or being 'a bit mad'.
In the song, the phrase "Tá com raivinha, bê?" (Are you a little mad, babe?) is used playfully to address a partner who is upset. It's an endearing way to acknowledge their anger while also trying to de-escalate the situation and move towards reconciliation, often with a romantic or intimate resolution in mind.
The whole song is one argument being talked down. It opens mid-quarrel — "Eu, psiu, vai começar de novo?" ("Me, shush, are you going to start again?") — and the singer spends the first verse asking for the floor: "Calma aí, deixa eu falar" ("Calm down, let me talk"), then "Que tal a gente conversar?" ("How about we talk?"). His case is that the fighting has become routine and that it costs something: "Todo dia é discussão / Faz mal pro coração" ("Every day is discussion / It's bad for the heart").
Then he changes the subject, and the proposal arrives as a punchline: "Que tal hoje a briga terminar no meu colchão?" ("How about today the fight ends on my mattress?"). From there the hook asks "'Tá com raivinha, bê?" ("Are you angry, baby?") over and over and never waits for the answer — "Fecha os olhos, cala a boca / Eu vou te fazer esquecer" ("Close your eyes, shut up / I will make you forget"). The batidão under it does the same thing the singer is doing, looping the same four lines until the argument has nowhere left to go.