Destiempo literally translates to "untimely" or "out of time." It's a less common word than its components might suggest, making it interesting and memorable.
In the song, the lyrics "Bésame, a destiempo" (Kiss me, untimely) suggest a kiss that happens at an unexpected moment, perhaps when it's not convenient or when it goes against the natural flow of things. This adds a layer of passionate urgency and a hint of forbidden romance to the request for a kiss.
Camila's "Bésame" is a plea for a kiss that erases everything else. The trio built their sound on close harmonies and understated production, and here that restraint makes the request land harder: "Bésame, como si el mundo se acabara después" (Kiss me, as if the world ended afterward). There's no elaborate metaphor chasing the feeling, just one command repeated with small variations, each time asking for something more total: "Bésame, y beso a beso pon el cielo al revés" (Kiss me, and kiss by kiss turn the sky upside down).
By the last verse the song drops its polite framing entirely: "Bésame, así sin compasión" (Kiss me, like that without compassion), "Quédate en mí sin condición" (Stay in me without condition). It's less about persuading someone to fall in love and more about wanting the kiss itself, right now, on its own terms.