I'm looking after my DB's 15 year old dog this week, along with my own 10yr old ridgey. They usually get along quite well but there have been issues in the past. My dog attacked DB's dog once when I bent down to pat DBs dog first- had to throw water over them! Then another time, DBs dog attacked mine when I gave a treat to my dog first at DBs house, tore a strip out of my dogs ear!
So how do I treat them while at my house? Should I always feed/stroke one dog before the other? If so, which one? There doesn't seem to be an 'alpha' dog iyswim. They're both getting a bit doddery on their legs now so I don't want to cause any OAP upset 
They're both female btw.