Originally Posted by Lilie
In a 5 month old puppy it isn't dominance nor sexual in nature. It is more likely a behavior the pup is exhibiting because it isn't sure what behavior is expected of it. It is excited (play) and is unsure how to proceed.
It isn't an acceptable behavior and needs to be corrected - but you need to make sure the pup is aware that it's not being corrected for the what caused the behavior (wanting to play). The best thing to do is make it a non-event. When the pup starts to hump just gently push it off and say 'quit', then continue to play. Making it an event by laughing or shouting for someone to come see (etc.) could be understood as a reward for the behavior to the pup.
Our approach has been to ignore this behavior unless he he humping something inappropriate.
Linus humps his fleece crate blanket from time to time. We call it his "girlfriend". As far as we are concerned, he can go to town on his girlfriend. We don't seem the harm in it.
But he also likes to take my wife's pillow off the bed and hump the pillow. We usually just take the pillow and tell him to go find his girlfriend.
Linus van Pelt Haus Juris. My Sweet Babboo, born March 17, 2014.
Madeline Ronan Heart (Maddie) Dec 1997 -- November 22, 2013 Rescue GSD, Sable