Desaire translates to "snub" or "slight," a dismissive gesture that makes someone feel rejected or unimportant. It is a less common word in everyday conversation, which makes it stand out in a song.
In "Me encanta este desaire, este es mi último baile" ("I love this snub, this is my last dance"), TINI turns something painful, being snubbed, into an oddly liberating final gesture, almost celebrating the end of a relationship.
TINI spends this song getting out of the room before anyone can throw her out of it. "Así que no me extrañes, antes de que me dañen" (So don't miss me, before they hurt me) is the deal, and she offers it first, which is the whole point. The verse that sets it up is sharper than the chorus: "Miradas amargas, focos que me apagan" (Bitter looks, spotlights that switch me off) is an odd thing for a pop star to admit, that the lights are what drain her rather than what she came for.
What keeps it from turning into a sulk is "Me hice amiga de este sentimiento" (I've made friends with this feeling). She is not fighting the hurt, she is on speaking terms with it, and the shrug that follows is "Calma, que el dolor nunca es eterno" (Easy, pain is never forever). Then listen to the last four lines: the chorus comes back with two of its phrases traded, so it now runs "Este es mi último baile antes de que me dañen" (This is my last dance before they hurt me) where the line about not missing her used to sit. Same words, new order, like someone rehearsing the exit until it comes out right.