Rascabicho is a highly colloquial and vulgar term in some Spanish-speaking regions, particularly Puerto Rico, where Omar Courtz is from. It literally translates to something like "dick-scratcher" but is used as a derogatory insult, similar to "asshole" or "dickhead" in English.
In the song, the artist uses this strong word to refer to his partner's ex, telling him not to mention her: "Dile al rascabicho de tu ex que a mí no me mencione" (Tell your ex-asshole not to mention me). It's a very direct and aggressive way to assert his claim and dismiss the ex, making it a memorable and impactful word choice that stands out from more common insults.
"WO OH OH" is Omar Courtz and ROA singing about a love that feels all-consuming, even a little reckless.
The verses lean into how intense the connection feels: the singer describes praying for this person, missing them before they even met, and feeling like their souls have crossed paths in a past life. It's over-the-top and playful at the same time, comparing the couple to Simba and Nala, or Bieber and Selena.
The "woh oh oh" hook captures that feeling of being so wrapped up in someone that the rest of the world disappears. Between the romance, there's also plenty of raw, physical desire, and a few brags about not needing anyone else once this person is around.
It's a song about wanting someone so much that logic doesn't really apply anymore.