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."