Sendo is a cool piece of Puerto Rican slang that means 'tremendous', 'huge', or 'massive'. It's a powerful adjective used to emphasize the size or intensity of something, and it's a word you'll rarely find in a standard Spanish textbook.
In the song, Rauw Alejandro says "dio sendo apretón", which can be translated as "she gave a tremendous squeeze". Learning words like sendo is a great way to understand the regional flavor of music and sound more like a native speaker.
The whole song hangs on one offer, and it is right there in the title: si te pegas, if you come closer. Rauw Alejandro spends the night making the case, and the deal he proposes is deliberately small, esta noche eres mi nena y yo tu nene, tonight only, nothing promised past sunrise. He builds the scene out of very specific details rather than grand declarations: Don Omar playing in the car, a TikTok that gets engagement, a party that runs until the wall is holding both of them up.
Miguel Bosé turning up here is the surprise, a Spanish pop legend dropped into a Puerto Rican club record, and it is what makes the track feel like a wink rather than a boast. The Spanish is pure Caribbean party register: endings swallowed whole (ocupao', prendía, pa'), wepa used as pure punctuation, and perrear treated as a completely ordinary verb. Loud, flirtatious and totally uninterested in tomorrow.