The idiom 'pin cushion' refers to some who has a lot of body piercing. Although can take on many forms. it is most commonly used refer to a person with many piercings.
An etui.
From the sport of wrestling.
as neat as a pin
"alfiler" is the answer i belive your looking for. pendejo
Nicknames for the name Robert are Rob, Robbie, Bob, Bobbie, Bobby. A particular type of hair pin is a "bobby pin" or "bobbie pin".
This isn't an idiom because you can figure it out if you look up the word "pins." It is a SLANG term meaning legs, so you knocked him over.
An etui.
A pin cushion
A pin cushion.
Pins and pin cushion
Freakshow - 2013 Human Pin Cushion 1-4 was released on: USA: 7 March 2013
Sea Urchin
Sea Urchin
From the sport of wrestling.
Pin cushions can be bought from any major retailer that happens to have pin cushions for sale. Pin cushions are useful for any one who needs to pin for cloth down.
Pins have sharp points, so if you are cautious, you can avoid puncturing your skin. Possibly you intended to ask about pin cushions, not pin caution. A pin cushion is a little pillow into which pins can be stuck, in order to store them conveniently. The reason for using a pin cushion is that it positions the pins for you, with the head outward and the point inward, so they can be more easily grasped.
It is used to keep the sewing pins on so they don't get lost and for safety.