mess around

/M EH1 S ER0 AW1 N D/
verb
  1. 1

    To fiddle idly.

    โ€œThe kids sat there messing around with leaves and blades of grass because they were bored.โ€

  2. 2

    To joke, kid, or play.

    โ€œDon't mess around with electricity if you don't understand it.โ€

  3. 3

    To have a sexual relationship, especially one which is non-commital.

    โ€œRumor has it that he's messing around with his secretary.โ€

Source: https://en.wiktionary.org/wiki/mess%20around