behavior during mating

Question
My golden retriever is in heat. For the last 3-4 days she has been very hyper..wanting to stay outside, panting, running around the house, etc. I have kept a close eye on her when she is out because of a stray dog in the neighborhood. However, last night I was distracted for about 10-15 min. and when I went to check on her, there was that dog with her. Today, she is doing nothing but sleeping! Does that mean her and that dog mated or is she "out of the mood".

Answer
Don't relax now.  Rather than a sign of mating last night, her change in behavior more likely means her fertile stage has passed.  If she mated last night, and is still in the fertile stage, expect continuing, strenuous, creative efforts to find a male.  Dogs don't do quickies.  Unless she was out there at least a half hour, likely they did not have time to mate.  

As much as she may need it, do not rush to bath her as her season winds down.  Until all the swelling is gone, she is still open and in danger of infections.  Don't be alarmed is her nipples swell and she develops a udder.  False pregnancies are very common.  A vet or other experienced people can feel developing puppies about a month after conception.   

After this is over, why don't you have her spayed and not go through the hassle again?  If you are considering breeding her, go to www.akc.org, and read their material on breeding.