Is there a secret to the twist lock plugs?

[Hwk-I-St8]

I bought stuff to make some power cables to get my electric going. I have a cable with a 14-30 socket. I have a 14-30 plug that is not put together on a cable yet and I wanted to see how it works so I connected it to the socket. Now I cannot get them apart. It seemed like I was able to twist it a quarter inch or so when it went on, but now it won't twist the other way and won't come apart.

Help! How can I get this apart? Is there a trick?

 

[day_trippr]

Push in and turn?

 

[augiedoggy]

Push in and turn?

reverse to unplug...

 

[Soulshine2]

twist lock cord plugs are a pain in the ass ...push in and twist.