Dá preferência literally translates to "Give preference". It's a direct and commanding phrase that's the heart of this fun, flirtatious song.
Instead of a more subtle approach, the singer gets straight to the point, telling the girl: "Se for beijar na boca hoje... Dá preferência pra mim" (If you're going to kiss someone today... give preference to me). It's a perfect example of the playful confidence in Brazilian Sertanejo music, essentially meaning "Choose me first!"
This song is a perfect example of Brazilian party flirting! It's set at a churrascada (a barbecue), and the singer, Thiago Brava, walks right up to someone he's just seen. He's polite, starting with, "Oi, boa noite como é que cê tá?" (Hi, good evening, how are you?), but he gets straight to the point.
His main goal is to be the first in line for a kiss. He tells the person, "Se for beijar na boca hoje faz assim / Dá preferência pra mim" (If you're going to kiss someone on the mouth today, do this / Give preference to me). His reasoning is simple and pretty funny: he deserves it because "eu fui o primeiro a pedir" (I was the first one to ask). It's a confident and playful song about shooting your shot at a party.