Acetato literally translates to "acetate", a type of plastic. However, in the context of music and urban slang, it's often used to refer to a vinyl record.
In this song, Sech uses acetato to evoke a sense of nostalgia and permanence, contrasting it with fleeting relationships. He sings "Cero vuelta, acetato" (No turning back, vinyl record), implying that some things, like a deep connection or a painful memory, are fixed and can't be easily changed or erased, much like the grooves on a record.
Sech's "Aquí Pensando" is all about that late-night, can't-get-over-you feeling. Our guy is out at the club, but even as the hours tick by from 3 AM to 5 AM, he's stuck in his head, thinking about an ex. He tries to escape her memory, saying, "Tu recuerdo me sigue por más que me escapo" [Your memory follows me no matter how much I escape], and even though he's trying to move on, he admits, "No quiero otro culo, te juro que trato" [I don't want another ass, I swear I try].
He's clearly struggling, wondering if she's with someone else right now ("Que ahora mismo estás chingando con él" [That right now you're hooking up with him]) and wishing he could be a superhero to rescue her. There's a mix of regret and longing, as he remembers how he "almost bit" her, and even if he got Alzheimer's, he'd still remember her. It's a relatable track for anyone who's ever found themselves wide awake, replaying old memories and wishing things were different.