try it on

verb2

1. •
   (informal) To test someone to see how much bad behaviour they will tolerate; to try to deceive someone to see how gullible they are.

   • “We must not submit,” said Mr. Eager. “I knew he was trying it on. He is treating us as if we were a party of Cook’s tourists.” — 1908
2. •
   (informal) To try to start a sexual relationship (with someone).

   • No, this was only a young man trying it on with a girl, in that light, undergraduate way in which this kind could snap back. — 1969