Depends. If the person is already "leg pressing" the weight (think 90% of what you see people doing in the gym), then I'll exaggerate my cue and tell them to reach back with their hips a whole lot. If their already reaching back too far with their hips to the point that there is very little if any forward knee travel, then I'll tell them to sit straight down between their thighs. The cue should fit the individual.
-Stacey