You sit down and start fussing your older dog, and the young one arrives before your hand has settled. They push their body in between, shove their head under your hand, and grumble when the other dog keeps their turn.
Owners call this jealousy, and the word is close enough for a start. What sits underneath it is plainer. Fuss is one of the best things in the room, your other dog has it, and your adolescent does not.
This is not about who is in charge, and it is not a test of you. It is a young dog with a want and no polite way to ask.
How this differs from pestering the other dog
Two adolescent problems look similar from the sofa. One is your dog going at the other dog for the sake of the game. The other is your dog going at the other dog to get to you.
The second one stops the moment the other dog leaves the room, and starts the moment your hand lands on them. That is the one this page is about.
If your dog is body-slamming the other one whether you are there or not, that is a different page. The work is not the same, and the two do not respond to the same plan.
Stop the rehearsals first
Do not fuss either dog while both are crowding you. Stand up, say nothing, and stop. Fuss comes back once the bodies have settled.
Give each dog their fuss alone, in a different room. Fuss should not be a shared event your dog has to win.
Put your young dog behind a gate, or on their mat with a chew, before you start. They cannot practise the shove from there.
Move the other dog out of reach with a house lead left on the harness, rather than with your hands on their body.
Teach something better to do
Behaviour change is built from management plus reinforcement together, and everything above is the management half. The reinforcement half is a place to be that pays better than shoving in does.
Put a mat 6 to 8 feet from where you sit, and feed your dog for lying on it.
Start with no other dog in the room, and build up to 3 minutes of lying there.
Add the other dog next, at a distance your dog can still hold, and pay both of them for staying put.
Work below the level that pushes your dog past what they can manage. That is the condition for learning here as much as anywhere.
Relaxation is trained as a behaviour in its own right, in short repeatable sets. A dog who can lie down and stay down has somewhere to put the want, which telling them off never gives them.
The part owners get wrong
Do not tell your dog off for pushing in. Punishment-based approaches are associated with fear, avoidance and defensive aggression, and the want is still there afterwards.
Do not hold your young dog still and fuss the other one in front of them. That rehearses the exact competition you are trying to end.
Do not save all your fuss for the moment your young dog is excluded. Pay the lying down first, before the pushing has a reason to start.
Reward-based methods are what the veterinary behaviour guidance recommends, and survey work associates them with higher reported responsiveness and fewer reported problem behaviours. This is one of the places where that matters most.
Safety note
Get help now if the grumbling has moved on to growling, snapping, a hard stare or a bite, or if either dog has been injured. Separate the dogs whenever you are not there to watch, and speak to a qualified behaviour professional who works with reward-based methods. Book a veterinary examination as well if this arrived suddenly, or if either dog has stiffened up, gone quiet or stopped eating. Pain frequently presents as a change in behaviour rather than as obvious lameness.
What to expect
The pushing usually eases once the reason for it has gone, because a dog does not compete for something that is no longer contested. The grumbling is the part to take seriously, and it is the part that needs a professional rather than a mat.
Two dogs who both want the same person can learn to take turns. Most of that is arranged by you, not worked out between them.
If the shoving, the barking at you and the pestering are all happening at once, the Assessment will name the pattern underneath. It is free, takes about 3 minutes, and asks for no email address.
Today's version, in one line: fuss the older dog in a different room, and pay your young dog for lying on their mat.