Bendito literally translates to "blessed" or "holy." However, in many Spanish-speaking contexts, especially in informal or exclamatory uses, it can function as an interjection similar to "Oh my goodness" or "Damn it."
In this song, "Ay, bendito" is used as an exclamation of surprise, frustration, or intense feeling, often when something is overwhelming or irresistible. The singer uses it to express how strongly he's affected by the person, highlighting the intense desire and attraction he feels.
The setup is one line: "Ella cree que porque es mi pana" (She thinks that because she's my friend), "No le tengo ganas" (I don't want her). Everything after it is Mora explaining, at length, how wrong she is. "Ay, bendito" is a Puerto Rican expression closer to "oh, bless" or "poor thing", the sort of thing you sigh over someone else's bad luck. Here it gets handed to a completely different feeling: "tú me toca' y me derrito" (you touch me and I melt).
What makes it fun is how practical it gets. No grand declaration, just logistics for slipping out of a party unnoticed: "Después de dos tragos, nos vamos" (After two drinks, we leave), "Si quieres yo salgo primero" (If you want, I'll go out first), "Y tú sale' en diez" (And you come out in ten). The Spanish is the spoken kind with half the consonants filed off (sale', toca', pa'), and the best line is a joke: "Diablo, tú tienes to' los cheat codes" (Damn, you've got all the cheat codes). Ovy On The Drums keeps the beat unhurried underneath, so a song this blunt never sounds like it is trying hard.