Eriza la piel literally translates to "bristles the skin" or "makes the skin bristle," but it's an idiomatic expression that means "to give goosebumps" or "to make one's hair stand on end."
In the song, the lyric "Sabes que ese bolero me eriza la piel" means "You know that bolero gives me goosebumps." It's a vivid and evocative phrase that conveys a strong physical and emotional reaction to music, making it a memorable and interesting expression to learn.
"Bailas" is a love song by Ximena Sariñana about falling for someone the moment she saw them dance. She notices small, genuine details about this person: they still give flowers, they don't hide behind filters, they write songs and don't break hearts. The chorus circles back to the dancing itself, close and slow, while they whisper that they love her.
The bridge leans into the idea that no summer lasts forever and winter will come, but she wants to use that as a reason to grow closer rather than pull away. She even references the classic bolero "Bésame Mucho," tying her own romance to that tradition of longing and closeness. By the end, she keeps repeating that dancing with this person filled something that was missing in her.