Absolutely do NOT tie your ponied horse to your riding horse. For a well schooled horse 100% broke to ponying - like a polo pony- it could be done, but not to a youngster. Too much can go wrong too fast.
The classic method of ponying is to have the ponied horse to your left with it’s head level with your knee on a short lead, close enough for you to be able to touch it easily. That way you can control it better, and have it follow better. It will also be more inclined to behave. The bight of your lead should cross over your ridden horse’s withers/shoulder, through your right hand, so that the end will dangle on the far side. Your left hand should be free to hold the lead rope; your right hand on the ridden horse’s reins and the bight of the lead rope passing through. When you dismount, you will be standing between the two horses to easily lead them, separately, one on each side of you, back to the barn.
I would not recommend a chain over the nose – it can stop a horse dead in it’s tracks or cause it to throw up it’s head and yank your arm. Just do some ground work with the horse in a halter reinforcing your commands immediately when you say “slow up” or “back”. Thus, when the horse is being ponied, it will listen and obey.
Start your sessions in a small field or ring, just doing multiple circuits with the ponied horse on the inside. You can do obedience lessons with the ponied youngster that way, getting it used to the routine, before taking it out on the trail.
Once you get out on the trail, you will have laid the groundwork for both horses to consider the ride a working session, not a goof off session.
For my conditioning program I have been riding my 7 year old novice foxhunter, ponying my 19 year old endurance horse who (due to his competitive nature and years on the endurance trail) needed - in the beginning- constant reminders to keep his head at my knee. LOTS of reminders! He’s doing a bit better now that we are up to 6-7 miles a day, letting the younger pony do the leading… except when the old timer lets loose the “power trot” going up or down hills, making the poor youngster huff and puff just to stay ahead of the game. :rolleyes:
No doubt, I will have the best conditioned pair of ponies this fall for hunting and endurance …with only half the time expended.