There are many ways of putting DC electrical signal into the brain. Some laboratories conduct the current through sponges, while others use high density clusters of stimulators. There is a tremendous amount of research trying to find the best intensity of stimulation, type of stimulators, stimulation pattern, and location of stimulation.
In general, DCS most commonly involved putting two stimulators on your head. These usually are wet with saline or a conductive gel. We wait to make sure the wet is absorbed by your skin, which helps us get a good connection (impedance). Usually there will be a few seconds while the charge comes up to its full intensity. The stimulation will remain on around 20 minutes. Then, the stimulation is ramped down.