Regañar means "to scold" or "to tell off." It's a common verb in everyday Spanish, often used in family contexts.
In this song, Bad Bunny uses it to add a surprising and humorous twist to his tough-guy image. He warns his lover not to scratch him or leave marks, singing, "Que después mami me va a regañar" (Because then my mom is going to scold me). This playful confession that he's still afraid of his mom is both funny and relatable, making it a very memorable line.
This song is a fun, flirty battle between two huge stars. Bad Bunny kicks things off with pure confidence, telling a woman, "Baby, no te hagas sé que te gusté" (Baby, don't pretend, I know you liked me). He sees that they've made eye contact and he's ready to make a move, but he calls her out for being all talk: "Tú hablas mucho y no haces nada" (You talk a lot and do nothing). He's very direct about what he wants, promising a one-night thing and being hilariously blunt about his intentions, even warning her not to give him a hickey because "después mami me va a regañar" (afterwards my mom will scold me).
But then, Jennifer Lopez steps in and completely flips the script. She's not impressed. She tells him she's heard this all before: "eres otro con el mismo cuento" (you're another one with the same story). She challenges him to prove he's not just another guy who thinks he's "muy macho" but can't "duran ni dos minutos" (last two minutes). The best part is her final power play, reminding him exactly who she is: "tú puedes ser Bad Bunny but I'm Jenny from the..." It's a perfect back-and-forth where she meets his bravado with her own legendary confidence, leaving you wondering who will win this game.