I started snort weezing last year. I did it on a cruising cow hown spike last year during the last week of bowseason. I just did it with my mouth, blowing air through a funnel I made with my release hand. He stopped and came stomping in looking for a fight. He got to 45 yards and skylined me in my climber. It was sure cool tho.
And yes, the blow is a warning call made by deer when the sense danger.