Flush with water? Why?
Clones can wilt rather quickly after being cut, depending on the environment and the plant... if the air is very dry, if the donor plant itself wasn't properly hydrated when you initially took the cuttings, etc. You don't need to "flush" the donor/mother plant, or any plant for that matter, proper watering will do fine.
Fresh cuttings have no root system, and thus lack the means to take in adequate water and maintain their turgor or rigidity (which results from cells being full of fluid). After cutting, dipping in rooting hormone (if desired) and placing the stem in moist media, the cutting itself needs to be kept in high humidity- under a dome, for example. They sell cheap, translucent plastic domes which fit over the black/white plastic nursery trays.
They'll need 3-4 days under the dome, sealed, although you can take it off briefly for air exchanges, to mist the cuttings or to add water to the tray. After 3-4 days you'll want to start venting it more frequently for longer periods, or slowly opening the vents on the dome. After about 7 days the vents should be opened fully and the dome removed. If the cuttings wilt, they need to be misted and placed under the dome again.