Arropado comes from the verb arropar, which means to cover or tuck someone in. It's a very cozy and tender word that evokes a strong feeling of being wrapped up snugly and kept warm.
In the song, Milo J sings, "Quiero despertar, arropado en tu manta" (I want to wake up, wrapped up in your blanket). He uses this word to perfectly capture the song's theme: a deep desire for comfort, safety, and intimacy with another person.
This song is about finding someone who feels like a safe place in a difficult world. MILO J describes an intense connection, one that makes his heart race. He tells this person, "Sé que el mundo es bruto, y ya sufriste mucho" (I know the world is rough, and you've already suffered a lot), and offers to be a source of healing and comfort for them.
The main feeling is a desire for simple intimacy. He sings, "Quiero despertar, arropado en tu manta" (I want to wake up, wrapped in your blanket). He's not sure if he should call this feeling love, but he knows it's powerful. He says he found this person when he was surrounded by "el cielo gris, y la soledad" (the gray sky and the loneliness), and their arrival made him feel like he was "en la luna" (on the moon).