Apantallar means "to show off" or "to impress." It's a colloquial and expressive verb that captures the essence of someone trying to make a big, often exaggerated, impression.
In the song, Gloria Trevi uses it when she sings, "Me va querer apantallar con su pistola" (He's going to want to show off with his 'pistol'). Here, it's used with a clear double meaning, referring both to a literal weapon and a crude euphemism for male anatomy, highlighting the boastful and often empty bravado of the
Get ready to feel empowered with Gloria Trevi's "20 Segundos"! This song is a sassy anthem where Gloria takes on a boastful 'bad boy' who thinks he's all that. She's not impressed by his attempts to show off, whether he's talking about his "bate y sus pelotas" [bat and balls] or trying to "apantallar con su pistola" [impress with his pistol] – which she quickly dismisses as just his cell phone!
Gloria makes it clear that this guy, who approaches her "como un rey" [like a king], doesn't stand a chance. She tells him, "Tú no me duras a mí ni 20 segundos" [You won't last 20 seconds with me], playfully challenging his bravado. She even pokes fun at his dancing, saying "Tú no bailas Gangnam Style" [You don't dance Gangnam Style] and "Tú no mueves las caderas ni pa caminar" [You don't move your hips even to walk]. It's a fun, confident song about a woman who knows her worth and isn't afraid to put a conceited man in his place!