These are not much fun to play with. Some are really bad -- some not so bad.
If your cow is flat from hooks to pins -- she is going to do it no matter what you do. I get a few cows in here that are like this, some of them are even higher inthe pins than the hip bones, and are hell on wheels to breed and even worse to flush.
Here is what I always do on these -----
BEFORE you insert the gun, set it up so that you have one of those little thin slip on sheath covers on it, get a good hold of the cervix just before she sends you a contraction, and as she humps uo to try and push you out -- pull the cervix FIRMLY towards you as she pushes. They will usually put a hump inthier back about then, and if you timed it right, you can get all the fluids to pour out. Quickly get your covered gun into the proper position at the end of the cervix and then, not before, pull the sheath protector hard enough to punch a hole in it so the gun is now free and get thru that cervix before she has another contraction. Once you are in there -- the fluids will not follow and you can be safer gettnig the semen deposited fluid free into the uterus.
Your main concern will be a low grade infection inside the cerviz itself from all the urine and bacteria. Once in a while I have used a 10% mix of Gentocin with sterile saline and infused them 12 hours after breeding to help this. It has worked, but it is a lot of time!
Not much else you can do to a true wind sucker -- sewing will only casue more irritation, not really worth the effort or risk.
Good luck -- Terry