When you grab a nug of weed and put it in a bag or container of kief and shake it all up then remove the kief covered nug and proceed to "bake" it via pipe, bong etc.
Person 1: "aye i got some bud wanna toke?"
Person 2: "hell ya mayne i got some kief!"
Person 1: "you thinking what im thinking?"
Person 2: "Shake and Bake!!"