Through range, of course. Mash can take out his iron wand, sculpt it into a tennis racket, and start wailing on Inuyasha from a range with projectiles like rocks or the aforementioned ice. Mash doesnt even need his iron wand for this, as he can pick up anything, like a rock, rock throw it at the enemy while it circles back to himself.
I see, so the Purified Yokai form is his regular form?
Also, if Inuyasha does ever relent with the suction holes, Mash can fly as well, so Inuyasha flying wouldnt be much of an advantage.