Pulgares translates to "thumbs." While seemingly simple, it's an interesting and somewhat unexpected word to feature prominently in a song's lyrics.
In this song, the phrase "con mis pulgares" (with my thumbs) appears in a tender context: "Y acá me seca sus lágrimas con mis Pulgares" (And here he dries her tears with my thumbs). This imagery of using thumbs to gently wipe away tears is intimate and specific, making the word memorable and giving it a unique emotional weight within the song.
This song is all about a deep desire to be with someone special, every single day. The singer wants to wake up next to this person, to "mirar tus ojos y ambiente" [look into your eyes and your surroundings]. It's a sweet picture of wanting to be fully present in their life.
He's ready to do anything for this person, even saying "todo a tu antojo" [everything to your whim] and creating whatever they want. There's also a really tender line about drying tears: "mi cama seca tus lágrimas con mis pulgares" [my bed dries your tears with my thumbs]. It's a very intimate and comforting image, showing how much he cares and wants to be there for them. He's hoping that, eventually, he'll truly matter to them.