Pichándome comes from the verb pichar, a popular slang term in Puerto Rico that means 'to ignore' or 'to stand someone up'. It's believed to derive from the English word 'pitcher', as in a baseball pitcher who 'throws away' a ball.
In the song, Rauw Alejandro sings "Estás molesta pichándome" (You're mad, ignoring me), expressing his frustration that his ex is giving him the cold shoulder. Learning this unique word is a great way to understand the specific flavor of Caribbean Spanish.
Ever run into an ex and suddenly all the memories come flooding back? That's exactly what's happening to Rauw Alejandro in "Pensándote". He sees a former flame and admits, "Ayer te vi, te ves mejor" (Yesterday I saw you, you look better). He immediately wonders if she still thinks about him or if she got tired of waiting and found someone new. His solution is pretty direct: "Dame esta noche pa' hacerte recordar / Que ninguno te va a dar como yo" (Give me this night to make you remember / That no one will give it to you like I do). He's not asking to get back together, he's just asking for one more night.
This whole song is basically his argument for why she should say yes. He spends the entire day thinking about her, specifically remembering their intense physical connection. He recalls very specific scenes, from watching her in his bed to their trysts in motels in Aguadilla, Puerto Rico. He knows she's mad and ignoring him—"Estás molesta pichándome" (You're mad, ignoring me)—but he's still confident. He even mentions seeing her go viral on TikTok and says that even though other guys want her, he's "invicto" (undefeated). It's a bold and steamy plea to relive their past, even if just for a few hours.