Parquear is a common example of 'Spanglish,' a blend of Spanish and English. It's an adaptation of the English verb 'to park' and is widely used in Puerto Rico (where the artists are from) and other parts of Latin America instead of the more traditional Spanish word, estacionar.
In 'Desesperados', the singers use this colloquial term to set a scene of urgent passion, explaining that they were so desperate they had to pull the car over immediately. It's a perfect example of how modern, regional slang makes its way into music.
Desesperados is all about pure, uncontrollable impatience. Puerto Rican stars Rauw Alejandro and Chencho Corleone tell a story where passion completely wrecks their original plans. They actually booked a hotel room—Tengo reservado el hotel ("I have the hotel booked")—but the urge is so wild they cannot even wait to drive there. Instead, they pull over right away: por eso nos tuvimos que parquear / Atrás nos espera el asiento ("that's why we had to park / the back seat is waiting for us"). It is blunt, sweaty, and hilarious how fast common sense flies out the car window the second things heat up.
Linguistically, the track leans heavy into street slang from Puerto Rico. You will hear bellaquera multiple times, which translates directly to intense lust or horniness (la bellaquera nos domina, meaning "the lust overpowers us"). Then Rauw throws in a geographical nod: De la metro a Mayagüez ("From the metro area to Mayagüez"), pointing across the entire island from the San Juan metropolitan region on the northeast coast all the way out west to Mayagüez. When you are willing to pull over and fog up car windows between those two points, you are officially desesperado (desperate).