WOW! loki sounds like a level headed dude! It's amazing how gentle and polite rotts are. They have the power to back up what they say too, but rarely use it. Grace loves to butt check other dogs to gain her advantage during play too. it's kinda funny and i like to see other dogs bully her back. she needs it really.
but when she's trying to put someone or another dog on notice that "The next time you do that, it's gonna hurt", she firmly punches you with her nose. she won't bite the first time or shread or tear or bear her teeth. after a big ole show of force, which is scary enough, she just punches you hard with her nose.
She does it to me once in a while too but for much different reasons. it's usually to say "HEY MOM! we've been standing in this same spot far too long! you done yet? put the camera down and let's walk." then we're off to our start, stop sniff walk.
I think Rotts have so much personality... the hyper ones like Grace and the mellow ones alike. They are just big babies who know their own strength.