play fast and loose with someone/something
play fast and loose (with someone or something)
To act recklessly, unreliably, irresponsibly, or thoughtlessly toward someone or something; to treat someone or something with a lack of respect or seriousness. I know these tabloids play fast and loose with the truth, but they're such a guilty pleasure of mine! I can assure you that I am not playing fast and loose with him; I intend to marry him some day. If you're going to play fast and loose, go work at another firm. That's not how we operate here.
play fast and loose (with someone/something)
in. to treat someone or something carelessly or unfairly. The broker played fast and loose with our money. Now we are nearly broke.