Volcán literally translates to "volcano". It's an exciting and somewhat unexpected word to find in a reggaeton song, making it memorable.
In the song, Ozuna uses "volcán" as a metaphor for intense passion and desire. He sings, "Te tengo una cita en el volcán, súbete rápido, que se me va a explotar" (I have a date for you at the volcano, get on quickly, because it's going to explode on me). This imagery vividly conveys the overwhelming and explosive nature of his feelings, creating a sense of urgency and excitement.
The whole song runs on one metaphor and never bothers to disguise it. Ozuna books a meeting at a volcano, "Te tengo una cita en el volcán" (I got you a date at the volcano), then hurries her along with "Súbete rápido, que se me va a explotar" (Hop on quick, it's about to blow). What leads up to that is almost courtly by comparison: a shot for nerve and "Un bailecito pa' conquistarte" (A little dance to win you over), before the answer comes back as "No necesitas mucho pa' convencerme" (You don't need much to convince me).
Beéle's half drops the tempo and softens the pitch. He calls her a cure rather than a prize, "Siempre serás mi antídoto para sanar" (You'll always be my antidote to heal), then hands the decision over to fate: "Si el destino, si el destino / Coincidió por ponernos acá" (If destiny, if destiny lined up to put us here). The last stretch is one line repeated four times with a different ending each pass, "Hoy terminamos con las ganas" (Tonight we kill the craving). And the hook holding it all together, "Entre tú y yo" (Between you and me), is the most modest phrase in the song, which is funny given the company it keeps.