If the runway is so short that you have to apply power to accelerate before configuring the aircraft, then conducting 'touch and goes' is probably not advisable, especially with electric flaps when an over eager student may attempt to get airborne whilst the flaps are still retracting, leading to the inevitable sink on departure....! I agree with configure first, then if sufficient runway remaining apply power.
I know the reasoning behind touch and goes is to give the student as much take off and landing practice as possible, but I wonder how many instructors also teach go around from the flare, or even go around after the main wheels are 'on' to simulate the situation where you have floated and have insufficient room to stop.
If the wheels are on the ground in the above simulated situation of not enough room to stop, do you then teach the 'go' as a go around in the landing configuration or do you raise flap to short field configuration (ie partial flap extended), then take off at minimum airspeed and climb at Vx?, or any other thoughts?