More on Sit Bodkin from Infoplease:

• Sit Bodkin - Sit Bodkin (To). (See Bodkin.) Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894 ...
• Bodkin - Bodkin A dagger. (Welsh, bodegy a small dagger.) Bodkin When he himself might his quietus make with ...
• Dictionary of Phrase and Fable: S - Definitions, origins, and illustrative excerpts for words, phases, and literary allusions starting with "S"