Peter_C,
It's on a Sun trike with the kool back seat using a leash and budgie cord.
I run him on the right side next to the curb. On the back left side middle of the seat bracing I hook the leash, run it around to the other side then wrap it around one loop of the seat bracing. (This gives the whole seat as leverage.) About 3/4 of the way down the leash I hook a budgie cord to it to use as control and so it doesn't get caught in the rear tire. (It's one of those leashes with the second loop close to the end to control your dog, so it makes it easy/secure to hook the budgie cord to.) On my end of the budgie I have a loop in it to go around my wrist.
I hope I explained it good enough you get the idea.
Mr Gnome