Hi I've tried mating up my small breed bitch she's 4 years old and I tried mating her yesterday on her 11 th day she was flagging and flirting outrageously lol but she'd let the stud dog mount her to a point and then she's snap at him we tried for about half an hour or so and wasn't getting anywhere so we called it a day  and decided to try again tommorrow which would be her 13 th day this is my 3 rd attempt and will be my last at trying to get her pregnant the stud this time around is proven with his 5th litter on the way so my question is why would she allow the dog to mount her to a certain point I think before he reaches a tie she turns and snaps at him is 11 th days too early for her perhaps I'm worried she's going to be like this on every attempt to get her mated on this season anyone had any experience with such bitches awaiting for some helpful replies

Is this her first litter?  Have you had her idexx tested to see if she is ready?

Also if he's an experienced stud dog he will know when the time is right.

My bitch did this too.  She would flirt and flag with anything but the stud dog.  Him she nipped and growled at!  Then I brought him back 2 days later and although to begin with, she acted the same again, within 10 mins they were in a tie and then mated happily 2 days later again.  Would've been her 12th and 14th days.  I go on the bitch not anything eles.  She'll know when it's time.

she'll probably snap before shes ready and also snap when shes gone over and the stud dog is still trying to chance his arm

Has she ever been mated before?  Is this going to be her first litter?