my bitch is so ready to be mated she is not intrested in stand she keeps showing her teeth at him, but at the other end her tail moves right out of the way she is on day 13

She may just need another day or so.  Is she a maiden bitch or an experienced one.  If the former she may just be a bit overwhelmed and with your reassurance and holding her gently but firmly may stand OK.  After that there is usually no stopping them :D  What is the males reaction, if he is backing off rather than trying to press the matter, it may still be too early.

sorry that would of helped yes she is a maiden bitch

he is backing off as she shows her teeth!

If hew is experienced then I would say she isn't quite ready, or needs to settle with him a bit more before allowing him to mate with her.

The back end is saying don't get discouraged, the front end says be patient yet.  Has her vulva and perineal area softened?

I took my maiden bitch to a stud dog owner by a very experienced stud dog owner. All I can say is, I am glad, as otherwise I might not have got her mated at all. It wasn't really what I expected, to be honest!

We mated her on days 13 and 15. After the first minute or two of hilding her, the stud dog owner suggested muzzling, then had to get a third person to help hold her, as she kept twisting her back end to 'escape'. Once they were in a tie, she calmed down, muzzle off and all was well. The second mating she was much less reluctant when she knew what to expect, although anxious for a second or two at first. We knew she was ready as we'd had premates done, and we ended up with 9 pups, so I'm pretty sure her objection was purely down to being a maiden.