Green’s Dictionary of Slang

1. a pimp [rons(on) = ponce n. (1)].

1960		J. Franklyn Dict. of Rhy. Sl.
1977		D. Powis Signs of Crime 199: Ronson Ponce.

2. the anus; thus dismissive excl. up your ronson! [ronson lighter = shiter n.].

1997		Roger’s Profanisaurus in Viz 87 Dec. n.p.: Ronson rhym. slang Arse. From Ronson lighter – shiter.
2016		Twitter 10 July 🌐 MURRAY HARD CHUFFS A BELTER UP THE GUY’S RONSON TO BREAK HIM APART LIKE A BALSA WOOD DILDO.