As this trick uses both hands....how do I practice this? I can't get anybody else to hold the coat. I want to be practicing for an hour or more at a time. Plus I don't want to reveal the secret to my family members.

any ideas how to do this?

You could just tie the jacket to a door knob with a piece of rope. But I don't see any problem with you revealing the secret to your family members though.

I practice this effect with a spoon and a vest. That way I don't ruin any coats.

Seriously, you could put the coat on a hanger and hang it from a hook at the end of a rope hanging from the ceiling. Or, clamp the arms of a coat to the backs 2 of chairs. You can get clamps from home depot, but I don't know where to get the chairs.

Lincoln
I used to help a friend practice this effect, but then he stabbed me in the back. OK, that is enough knife thru coat jokes for one post.