A gold pad, or gold cushion, is the surface on which gold leaf is worked as part of gold tooling. It is not neccesary in most forms of gilding, because the gold is transferred straight to the sized surface, and needs no place for intermediate working.
How to Get One
A gold pad can be purchased from a bookbinding supplier, or you can make your own.
To make a gold pad, take a piece of wood about 15cm x 30cm x 1cm (6 in x 12 in x 1/4 in). Cover it with three layers of cotton batting. Cut a piece of leather larger than your wood by about 2.5cm (1 in) in each dimension. Cover the cotton batting with the leather, flesh side outward. Fasten the leather to the edges of the wood with a staple gun.
You'll need to condition the suede surface of the pad. Dust it with baby powder or corn starch, then beat the pad until the powder doesn't transfer to the gold leaf later. This treatment will need to be repeated every now and then, or the leather will get greasy and stick to the gold leaf.
How to Use One
Use a gilder's tip or gilding knife to pick a leaf of gold up from the book it comes in. Don't use any of the methods that require oil to pick it up (e.g. a cotton ball rubbed on the face), they won't relinquish the gold to the pad. Blow on the leaf to flatten it. You can then cut pieces off as necessary to transfer to the final work, using either the tip or a cotton ball.