on chest...you rest at the bottom, your preference of touching or not. I dont touch. I do a single heavy set (higher than my working set for the day) of 3 reps, pausing at the bottom for 1 second.
For instance: if i do 3 sets of 10 at 315, then i prefer to do rest pauses with 365, for a minimum of 3, if i can do more GREAT.