I walk Sam and Ollie with a coupler that hooks onto their harness then onto one leash. They do pretty good when we are outside walking, altho Sam gets a lil impatient if Ollie wants to potty. Its a give and take. It takes about a block before they start being patient with each other.
I cannot take them into Petsmart on one leash tho as I think they think they are Pit Bulls, yanno, twice as big. They go Cujo, not tryin to bite anyone but they just sound like they are going to kill somebody. But if separate, they dont say a word