Moderate sedation. American society of anesthesiologists defined "conscious sedation" like this: it is a state if mind where there is purposeful* response to verbal or tactile stimulation, as far as the airway there is no intervention required to maintain it, there is adequate spontaneous ventilation (breathing is ok), and cardiovascular function is usually maintained. In short, patient is sleepy and heart;lungs ok.
"Twilight" Not a big fun of this term, but that what conscious sedation means - intravenous medications make you calm, drowsy, but one is able to see, hear and purposefully respond to verbal and other stimuli, albeit not clearly as in " daylight". The tricky part you may or may not remember doing that.