"Aprovecha" (Take advantage of it) is a warning dressed up as a favour. Eden Muñoz is talking to an old flame and telling her, pretty bluntly, that the door is open but not for long. She gets first pick only por derecho de antigüedad (by right of seniority), like she has earned a spot in line just by being there first.
The cocky part comes fast: Si es contigo o sin ti, al final, se va a hacer como quiera (With you or without you, in the end it's going to happen anyway). Then he admits temptation is chasing him como cazador a la presa (like a hunter after its prey), and other people are already saboreando tu olvido (savouring the moment you forget me) while she sleeps on it.
The chorus is all about second chances with a safety net. Le metemos reversa is Mexican slang for "we put it in reverse", meaning they can back out if nothing happens. And the ending gives away who is really stuck: Es más fácil que me busques tú, porque el orgullo, siento no me va a dejar (It's easier if you come looking for me, because I feel my pride won't let me). He wants her back, he just refuses to be the one who calls. Classic.
Listen for chiquitita (little one, a sweet nickname) in his shout-out, Es Eden Muñoz, chiquitita.