Asecho literally means "lying in wait" or "an ambush". It's a word you'd normally associate with hunting, not a romantic ballad, which makes its use here so powerful and interesting.
Carla Morrison sings that her lover's scent "me invita al asecho" (invites me to lie in wait). She uses this intense word to describe a deep, primal attraction—a magnetic pull so strong it feels like an instinct she can't resist. It's a poetic way to express an all-consuming desire.
Carla Morrison jumps straight into an overwhelming romantic obsession from the very first line of "Eres Tú". She wakes up with an intense craving to touch and hold someone, admitting right away: "Hoy desperté con ganas de besarte / Tengo una sed de acariciarte" ("Today I woke up wanting to kiss you / I have a thirst to caress you"). Using sed (thirst) gives the affection a physical, almost desperate pull, and she compares this person's presence to being intoxicated when she sings "Eres tan embriagante" ("You are so intoxicating"). For her, love is not subtle here; it acts like a force pulling her in, described as "Ese imán de una preciosa energía" ("That magnet of a precious energy") that sends physical signals straight through her body.
What makes the track stick with you is the quiet conflict near the end. She plainly admits "Tenemos planes diferentes" ("We have different plans"), yet it does nothing to stop the daydreaming. Even with divergent paths in life, she cannot shake the feeling because "mis venas, tan sutilmente / Disfrutan tanto quererte" ("my veins, so subtly / enjoy loving you so much"). She would rather keep replaying their kisses from memory than let reality ruin the mood.