Guaynaa takes reggaeton into cowboy territory here, and the whole song hangs on one cheeky command: "Monta, vaquera" [Ride, cowgirl]. The woman he's singing to is a star of the night: "Eres la más dura en la carretera" [You're the toughest one on the road], there's a waiting list of guys, and her hips carry "dos pistolas" [two pistols]. He keeps the western joke going all the way to a search warrant, "una orden de cateo", for the way she dances.
The chorus is pure flirting with a shrug built in. He asks "Dime qué es lo que hay" [Tell me what's up] and whether this is happening "o si se cae" [or if it falls through], and if not, "bye-bye, tell me why". It's very suggestive, so don't expect romance. It is fun, though.
Puerto Rican slang to know: "tú te la traes" means "you're amazing" or "you're too much". "Guayar" is to grind up close on the dance floor, and "perreo" is reggaeton's grinding dance. "Sateo" is flirting or messing around. "Mi chichi, El Guaynaabichy" is just his name tag, a play on his hometown Guaynabo.