Is my 4 month old Newfoundland puppy dominating my older dog?

My four month old 35 pound Newf puppy always tries to climb on top of my older 35 pound 14 year old Aussie. He lays on her when she is laying down, jumps on her when she is walking or walks beside her pressing his head down on her back. she won't put him in his place. Is he just playing or is he trying to dominate her. It does not appear sexual. My older dog is very timid and just tries to get away.When I am close by I intervene and say no but the behaviour continues.