We sometimes do this one we call chain punching. First start off in you fighting posture and shuffle forward and throw one vertical punch. Then shuffle again and throw two punches (alternating hands). Continue this pattern for as many as you can. then when you reach you peak come back down the latter. This must be done as fast as possible the WHOLE TIME, no cheating yourself. Remember, you only get out what you put in!
Duncan Leung's Drills are the best, he learned them and developed them with the best. You want to develop speed, timing, reaction ect.. basicly APPLICATION of THERY.. find a good school and watch his tapes. JMO YOu will not find these drills in OTHER schools. So why don't most schools train hard, and with good drills? ... good question. http://members.tripod.com/~Wing_Chun/Catalogv.html#Video4