> We were told she will be ready to mate tomorrow (day 8).
What was meant by she will be ready, do they mean that she is about to ovulate, has just ovulated and will reach the fertilise-able stage (two days after ovulation).
Some bitches will accept a male at or just before ovulation, and be happy to be mated over 5 days or more, and others will not until they are two to three days past at the optimum time, and maybe another day or two.
Also males may not mate a bitch until she is right on the dot, or others will happily mate anything that stands still.
I would never hold a bitch for mating in any restraining sense unless she was obviously receptive, biting the male is not receptive, though a bit of coy mock Resistance is something else, and an experienced male will know the difference as should his handler.
Once the dog has mounted then stopping the bitch sitting or moving forward at the crucial moment (once the ladder climbing has started, before they try to turn), and to support and keep still a bitch during the tie which many find irksome. some may even try to roll or pull violently, this is the stage where holding on tight is needed ;).