From Longman Dictionary of Contemporary Englishtrade on/upon something phrasal verbUSE A PERSONto use a situation or someone’s kindness in order to get an advantage for yourself If you ask me, they’re just trading on Sam’s good nature. → trade→ See Verb table
Examples from the Corpus
trade on/upon • All are being prosecuted for trading on a Sunday.• He has never found it hard to practice his goalscoring trade on his travels here, there and everywhere.• The delusion was welcome, and I traded on it consciously and preposterously.• No surprises there, as Stubbly never bothered usually with the floating drinking trade on Saturday afternoons.• Instead there operates a rebuttable presumption that the defendant did base his trades on the information in his possession.• Shares in Popular led gainers midway through trading on the Madrid Stock Exchange.• In late morning trading on Wall Street, the Dow Jones industrial average fell sharply, down 115.09 at 10,380.19.• Even small-time investors can place their money in venture capital funds traded on Wall Street. 