Doudou is a charming and affectionate term of endearment, similar to "sweetheart" or "darling" in English. It's often used in French Caribbean Creole and has made its way into popular French slang.
In this song, Niska repeatedly uses "doudou" to address a woman, asking her to dance or engage with him. It's a playful and endearing way to call someone, making it a memorable and culturally interesting word to learn.
Niska turns a phone call into a club chant here. The whole hook is one greeting said over and over, "Allô doudou" [Hello sweetie], and between the calls he plays the smooth talker who knows about four words of Spanish and uses all of them. It is flirting at full volume, and it gets crude fast: "Doudou, dis-moi la vérité" [Sweetie, tell me the truth] is followed by a question about her body count, so this one is strictly for adults.
Miimii KDS takes the middle of the song and flips the view, switching between French, English and Antillean Creole as she describes playing up the sexy act with her friends. Niska comes back boasting and brags that he leaves his rivals behind with "J'leur mets des vitesses" [I leave them in the dust], then ends on a line that is half joke, half confession: "Elle cuisine bien mais comme j'suis un salaud" [She cooks well, but since I'm a bastard]. For a learner, it is a crash course in the slang of French party rap, from "téma" (look) to "quillé" (wasted).