Green’s Dictionary of Slang

(UK black) fellatio, thus uck (someone) off, to fellate.

2015		Section Boyz ‘Trapping Ain’t Dead’ 🎵 Got a freaky gyal named Cece / Give me uck when I'm driving speedy.
2017		Unknown T ‘Bop with Smoke’ 🎵 Oi, this fucking uck is immense / The way that she slop on the top, issa mess.
2017		1011 ‘Kill Confirmed’ 🎵 Gyal ’uck me off, I ain’t bashing.