Derrites comes from the verb derretir, meaning "to melt". While it's a common verb, its use in this song is particularly evocative and sensual.
The lyric "Tu me derrites como hielo" (You melt me like ice) is a vivid metaphor. It beautifully conveys the intense emotional and physical effect the person has on the singer, suggesting a powerful attraction that causes him to lose his composure and be completely captivated. This imagery makes the word stand out.
Have you ever felt a connection with someone across a crowded room, a feeling so strong you don't even need words? That's the heart of "Vestido Azul" (Blue Dress). The singer describes an intense, unspoken understanding with a woman who captures everyone's attention, especially when she walks by in her stunning blue dress. He sees her as a naturally beautiful angel who "fell from heaven," looking like a model even without makeup.
The song is filled with anticipation. The singer is waiting for the perfect moment: when the right song plays, when her friend leaves, and most importantly, when her boyfriend gets lost in the crowd. While everyone else desires her from afar, he wants something more. He dreams of taking her somewhere private, where they can be alone in the low light and watch the sunrise together, turning a fleeting moment into a night-long connection.