Strangest technique I've ever heard! Nobody in their right mind would teach a student to deliberately fly an aircraft out of trim. How does this chap pass instructor renewals?
As for touch and goes and retracting flap after rotate, in an aircraft like a Bulldog with plenty of power this isn't a problem, but try it in a Cessna 150 (40 flap) and you'll struggle to get any climb at all.
Talking of interesting techniques, an instructor I knew always taught students to close the throttle at the threshold, regardless of how high they might be! Try that in a 150 on a dark night with 40 flap....oooh parachuting!!
Cheers
TJ;-)