How do I (teach my dog to)?
Some context:
I have a 1 year old GSD and a 2 year old Collie .
I have had them both since they were 8 weeks, so my collie was one when my GSD was 8 weeks.
Together, they are great. When we walk them they are fine. Separately, they seem to do well too.
The problem is when my fiance and I are...