Bellaco is a Spanish slang term that can mean 'horny' or 'mischievous', often with a connotation of being sexually suggestive or playful.
In this song, Jay Wheeler uses bellaco to describe a feeling of intense desire and arousal, especially on Fridays. He sings, "Tú sabes que me pongo bellaco los fridays" (You know I get horny on Fridays), and later, "Bien bellaquito, fiel a ese culo esperando" (Very horny, faithful to that ass waiting). It's a common word in reggaeton and urban music to express lust and sexual longing in a direct and colloquial way.
"Tiffany" is a reggaeton track by Jay Wheeler and Mora about missing someone on a lonely Friday night and wanting them to come back. The singer misses his partner's presence and the jewelry she wears, and promises he'll show up the moment she asks.
The verses turn explicit fast, describing a wild few days together at home, plenty of flirting, and a rival ("the loser") he wants her to leave behind for a weekend together. Underneath the bragging about money and looks, the hook keeps returning to one simple feeling: he doesn't want to spend Friday night without her.