Adding extra nicotine to a cigarette in order to get a high similar to meth or crack. This is very dangerous and nobody should do it. Ever. Of course meth and crack are both very dangerous anyway, as is smoking, so nobody should do those things either.
To add extra nicotine straight from the bottle to other drugs like crack or meth in order to increase the intensity and duration of the high. That also makes it easier to overdose.
Someone who constantly shows crack. They run around to the grocery store and do all their running around showing crack to everyone who tries to cop a peek.