Empinadinha is the diminutive of empinada, which means a 'tilt' or 'lift'. The diminutive suffix -inha adds a sense of smallness or endearment.
In the context of this song, it refers to a suggestive dance move where someone 'tilts' or 'lifts' their body in a playful and provocative way. It's a key word that captures the energetic and flirtatious vibe of the music.
This is pure party fuel, recorded live with the crowd right in the mix. It opens with the singer hyping the room before the beat even lands: "(E o Safadão diverte)" [(And Safadão gets everyone going)], "(Hoje eu 'to igual fogo)" [(Today I'm like fire)]. He's announcing the heat he's about to bring, not describing it after the fact.
Once the beat drops, the song is just one long dance floor dare. The hook, "A gata endoidou e deu uma empinadinha em mim" [The girl went wild and gave a little twerk at me], repeats until the whole crowd is shouting "Empina, empina, empina" [Twerk, twerk, twerk] back at him. Midway through he calls out his hometown crowd by name: "Alô, Caruaru, meu Pernambuco, diz" [Hey, Caruaru, my Pernambuco, say it], and closes the same way, telling his home state to "Faz barulho, meu Pernambuco" [Make some noise, my Pernambuco]. It's less a song about something than a song built to be shouted along to in a packed room.