The male and female end make a hard connection then move within the flow path, such as two disks mating flat then turning to allow flow. When returned to the closed position there should be no leakage and no material on open surfaces. There are several type and they all seem to have varying degrees of success.
With any of these "dry" couplings there will still be a few droplets of liquid lost whenever you decouple. It is just a question of how many drops. Some designs are better than others. These drips can be a major housekeeping problem in some environments. These couplings work by keeping the wet volume between the valves in each half of the coupling to a minimum. This usually requires some special nesting geometry in the valves and seals. But a few drops is better than a few cups.
