regarding the discussion about grip/grab...
from reading, it seems that some people make a couple automatic associations that i'd like to question or at least add to:
1. if a grip/grab is tight, this tightness travels up, and the rest of the grabber's body is necessarily tense/rigid/stiff, etc. (and thus, assumedly, they are unable to take good ukemi)
this creates the inverse:
2. if a grip/grab is light, the grabber is necessarily poised/in position to take better ukemi.
i think both of these assumptions are off for one reason:
it is possible to grip tightly, and yet, to isolate the wrist and hand so as to keep the rest of the arm (and thus body) supple and relaxed. just because the grip has tension doesnt mean it has to travel all the way up the arm and through the body.
i first encountered this principle while riding public transit;
if anyone has had to stand in a moving subway car/bus, holding on to one of the overhead hoops or bars while the train car wiggles and sways, they have felt this principle: the grip needs to be tight to hold on to the bar, but if the tight grip is allowed to travel up the body, the body will be easily be swayed by the movign car, making for a pretty bumpy travel; however, if the tight grip is isolated, and the rest of the arm (and shoulder, body, etc) is relaxed, then the body can stand quite relaxed while the arm (through the grip) acts as a buffer.
(i hope i explained that alright
i have to some degree been able to develop this ability on my path, and i have found that it has helped my ukemi tremendously.
on the other hand, i have felt grabs from others in different styles who have been taught to grab lightly for the sake of 'sensitive ukemi' and, while they did display a particular type of connectedness, i generally found them to be ironically disconnected from the martial reality of what we were doing...
also, ftr, i think it was clear that the OP's comment about 'testing' nage is not a challenge to the sanctity of the authority that Sensei holds; i agree with some that if we as training partners are not testing and challenging each other, then what are we doing? there are ways to challenge/test as friends and mates, without carrying the connotations of "arrogance" that some want to attribute in a blanket way.
just my 2 pesos.