Yanno that bitter stuff that you put on kids thumbs, to get them to quit sucking when they're too old... I actually got to like the flavor of it, and I don't remember exactly how I pilfered it from my mom, but would put it on ON PURPOSE before bed, so my thumb would have flavor.
Now if my mom had put Nyquil on my thumb instead, I'da broken the habit quick! Nyquil is icky!!!