A droud is a device which allows the user to send electrical impulses directly to the
pleasure center of their brain. It features heavily in
science fiction.
AFAIK,
Larry Niven may have invented the term, if not the concept itself. Typically, a socket for the
droud is
implanted into the user's skull; the droud itself is then used to connect the user to
wall current and hopefully protect them from overload, etc. Note, of course, that this is believed to be the most
addictive possible activity known to man.
Not to be confused with a device allowing stimulation of someone's pleasure center at a distance; this (according to Niven at least) is called a tasp.
Derogatory terms for droud users, from various sources, include juice junkie, wirehead, current addict, shaker and others.