This is a true story of two of our dogs, one Bug a wise older former street (dropped) dog, and Sasha the young impetuous, gullible, jealous girl. We have a sofa they sit on, usually they share it w/o problems, but sometimes Sasha will spread all out to cover the whole sofa, leaving Bug to have to sit on the area rug on the floor. Bug adores her sister and wouldn't ever get aggressive w/ Sasha, so when she wants on the sofa, this is what she does, she has done it many, many ...times so we know it is purposeful. She will loudly w/ pomp walk over to either Gary or I looking back to make sure Sasha is paying attention. When she gets to us she will ask to be petted, when we start petting her she will adjust her position to get us to scratch her back, and turn her head and look straight at Sasha and make grunting or happy noises to get her point across. Now Sasha can't handle anyone getting petted if she isn't, let alone a back scratch!!!!! She will watch w/ great interest until she can't stand it and she will come down off the sofa and present herself right next to Bug for her petting / scratching. As you have probably already guessed Bug makes a bee line straight for the empty sofa, to enjoy her spot. The funniest part of the whole saga is no matter how many times Bug does this Sasha NEVER gets it, she is soooo blonde.
Many years ago we had a blue heeler that would pull a similar stunt on her mastiff buddy. When he was snuggled up to "dad" she would run to the door like company was there, and then take his place when he went to investigate.