Blowing through a straw before using it.

This started when i was fairly young and my family was eating out at a restaurant (i dont remember where) and i was about to put my straw in my drink when my drunk ass dad fucking starts shouting for me not to put my straw in my drink. I freeze. The restuarant go's quiet. Everyone is looking at my dad like the insane person he is. Then he says he thinks he sees something in my straw. There was nothing in my straw. So i blow through it to blow out what ever is in it then i moved on with the family dining experience.

Ever since then i have to blow through a straw before using it or else i get a deep feeling of dread in my stomach.