Harvey has fun at everyone's expense. Usually it's not harmful to anyone (except in business... business is a whole other kettle of fish). Also, he is a shameless flirt when it suits his purposes. The flirting probably wouldn't be quite so overt if he was legitimately attempting to get her into bed. So, he'll call this slightly over-exaggerated for the sake of education.

It doesn't stop him smirking that self-satisfied smirk of his when she tries to counter him. Still leaned in nice and close, he grins against her ear and whispers, "Would you like me to be more subtle?"