For the future,
If the male is not hitting the mark, as often as not it is because the bitch is not quite ready and her tail is still in the way. When she is ready, the tail goes sideways and the way is clear.
Sometimes with an inexperienced male, he gets too enlarged to enter (it's a two stage process with dogs) and you have to separate them, give him a rest and a drink of water and try a couple of hours later.
If she is ready, and he is enlarged to the right amount but they are still not getting the act together, you have to guide the penis into the vulva, which is not without risk. The owner of the stud dog should be in charge of the mating and do what guiding is necessary as the male is used to being handled by its owner. (The stud owner ensures the male does not have any genito-urinary infection on a regular basis so the dog is used to being touched in the delicate area)
Once they are mated, a maiden bitch may panic as the tie is formed - this is the second stage of the enlargement of the penis and the dog is physically unable to withdraw. If she is trying to get away, the bitch has to be held to the male, preferably by her owner, who is at the sharp end. When the thrusting stops, the stud owner assists the male to lift a leg across so the pair end up tail to tail. They may stand, move a bit (keep hold) or lie down.
If all goes well the tie lasts about 20 minutes and it's not unknown for both dogs to go to sleep. To break the tie, the male licks and licks around the vulva until he is able to withdraw, don't try to get them apart until they are ready. The stud owner checks that the penis has fully retracted into the sheath at the end.

The last maiden bitch my stud ESS coverd was a lovely lady but very slippery. She was ready, allowed normal penetration and then rolled on her back as the tie was forming. I had to help my lad to turn so having started doggie fashion, they finished in missionary position and rolled over quite an amount of the floor during. Healthly pups nine weeks later I'm glad to say, but both the owners had to be quite intimate to keep the dogs together and our respectives spouses at the far end of the room were just doubled up with laughter.

Sgurr