If you don't have or want to buy a locking extension, you can just wrap a piece of duct tape around the top of the socket and the extension to hold them together.
That's what I do.

 

Yep duct tape, the handyman's secret weapon.

 

This one is easy, if you have a BMW motorcycle. There is a special bmw tool for torquing sparkplugs that fits inside the head of the R bikes. Bob's BMW has them. It's a one piece extension with the spark plug socket, no joint to separate. Very well made, but not cheap.

jrw

 

BMW motorcycle sparkplug socket is about 8 inches long. Holds plug perfect, is a one piece unit, and will let you thread in the plug very easily. It's slim enough to fit inside the heads of R bikes, and will fit easily into the opening for the MINI. I just changed plugs today. You can find it at Bob's BMW. They are not cheap, but what do you expect for well made german quality.

jrw

 

I suppose if you really wanted a custom single-purpose spark plug socket, a regular extension, socket and some Gorilla Glue could get you there for cheaper

The locking extensions can be used universally, and the socket won't pull off until you slide the button.

 

I know this thread is a little old, but I just used this tip to change the plugs on my other car (Accord). Used a plastic straw from a sports bottle. Couldn't have been easier. Thanks again to the MINI community