Laura - thanks for sharing those videos. We thought our two were "unique" in that biting face play. It goes on daily at our house. We have been trying to stop it or at least calm it down by separating the girls and redirecting their attention to something else. They are just about 7 months old and we weren't sure if it was a puppy thing or a behavior we needed to work to correct now to avoid more serious arguments later on. As I watched I told my husband, "we are not alone - you have to come and see this!". There is no hope for any of us. As long as it is play and not angry biting I guess we need to let them be and they will work it out.