Humedecer literally means "to moisten" or "to dampen." While it can refer to something simply getting wet, in the context of this song, it carries a more intimate and suggestive double meaning.
The singer laments that his former lover "no se humedece" (doesn't get wet) with her new partner, implying a lack of passion and arousal. He contrasts this with their past relationship, suggesting that with him, she truly belonged and experienced that physical connection. This makes humedece a provocative and memorable word in the song.
Christian Nodal's "El Amigo" is a super relatable song about that awkward feeling when your ex moves on, but you're still convinced you were the better partner. He starts by saying he's genuinely happy that her life isn't "negra" [black] anymore and that she's doing much better, even though it's clear he's a little salty about it. He admits he wasn't enough for her, saying "Él fue el que ganó, yo fui el que perdí" [He was the one who won, I was the one who lost].
But here's where it gets good! He's at a bar, a few drinks in, and starts spilling the tea. He says the new guy treats her like a queen, but she treats him like a friend! Nodal thinks the new guy is "fino" [classy], the type who drinks wine, but he knows her and says that's "no es su estilo" [not her style]. He even goes as far as to say, "Juntos no se ven tan mal, pero se veía mejor conmigo" [Together they don't look so bad, but she looked better with me]. He's convinced she'll be back in a couple of months because the new guy doesn't know how to truly make her happy. He even boasts, "Él le toca el cuerpo, pero soy yo el que al alma le toca" [He touches her body, but I'm the one who touches her soul]. It's a hilariously honest look at post-breakup jealousy and that lingering feeling that you were the one.