When your car windshield is frosted over and you are too impatient or hurried to scrape it all off or let it defrost so you are left with a small gap to see through, making you feel like you are driving an old tank.
I had to get to work so I couldn't waste time thoroughly scraping my car off. I drove halfway there looking through a tank slit.
The act of using Visine before smoking weed, as opposed to after. Some employ this method to ensure they don't forget to do so when they are baked or to lessen the discomfort of the Visine, which may be enhanced when baked.
"Yo you got drops? I'm gonna pre-sine it this time, I think it works better."
"Ya, good idea, I don't wanna walk out bakey-eyed."