I always introduce hobbles with the horse under control.
Usually with a lead rope attached, So I can stop them if they get too excited.
I think the best way to introduce hobble is lots of green grass underfoot, so the horses are happy to stay put as they graze and just shuffle around.
Don't put hobbles in a horse when his buddies are running to the far end of the lower 40 and he wants to join them. Put the horse in a situation where he is happy to stay put, put the hobbles on and then ask for a small step. He will stumble the first few steps, But will catch on pretty quick. After they know the hobbles are there, I leave them to graze and keep an eye on them. They figure it real quick, As long as they are not temped to really try to keep up or run away.