those flavor everything, tobacco, tea, corrnflakes, weed  :x

That’s a pretty cool idea.

what in the loving heck are they?

I haven’t tried these, but have only heard good things, mostly from weed and cigarette smokers. 

I think the idea is that you slide the white card into your pack of cigarrettes/cornflakes/weed/snuff/etc and it flavors it, don’t know how long it takes though. I remember reading that the brand Itsa sells these in gas stations and smoke shops in Canada. I’m pretty sure Itsa is marketed as as way to get around the flavored tobacco ban. I found a display box for Masons that advertises it for use with tobacco, coffee and cornflakes.