
Not an easy one..hard to 'battle' with a large breed.
It is best not to put on your fingers to administer, as no matter how much you wash your hands, they would not be sterile. I would agree with trying her first before your other dog.
Have you tried sitting her infront of your legs, facing away from you, then lift the head skywards to administer the ointment.
Maybe when she is really relaxed, say just about to wake or whilst your watching TV or the like....when she is least expecing it...but this would mean you would have to have the tube with you of course...