I'm working my pup (7 mo) through the FF process. I used a bench and started with a dowel then moved to a small bumper and then a large bumper. I have now moved to the floor (of the garage) and am working on the ear pinch. When I place the bumper on the floor about 4-5 paces away he runs out, retreives and when coming back starts to shake his head. Not violently but enough that when he gets back to heeling and sitting the bumper is just in his mouth, often cockeyed and with a tap I can knock it out of his mouth. On the bench I didn't have this problem and he doesn't mouth the bird. He does have a very soft mouth however.
I've tried to correct by repeating the command, 'hold' on his way back and it doesn't seem to help. When he gets back I place the bumper in his mouth the correct way and can walk away from him and he will hold it properly. Wondering if I just continue with this until it sorts itself out or is there something else I can try.
I haven't introduced birds into the FF process yet. That is the next step and I usually start with a frozen pigeon, frozen duck and then repeat with them thawed. Also wondering if he would hold a thawed bird better.