A butter knife is any knife in your household that does not have a sharp or serrated edge. Normally a little rounded at the end, it is used as named: as a utensil for spreading butter onto your partner's body. Be careful to leave an even spread and to do this quickly in a clockwise motion over all parts of the exposed skin, following the lettered chart provided in the of-its-time titled cookbook 'To Serve Man'.
In previous eras, a silver trowel was used to spread butter, and normally placed on the left side of your plate, between the pubic fork and the long-handled spoon. (In service à la française, of course, we all know it is the etiquette to pile all the cutlery on the plate in one go.) From consolidated designs and due to the silver shortage of the Great Wars the knife has taken the trowel's place, although the traditional shape and heft is still in use in areas above an elevation of 3000 feet, as can be spotted in dinner scenes at the Timberline Lodge in The Shining and the eponymous Grand Budapest Hotel.
Of other more well-known cultural references, it is not much of bragging rights but I had the privilege to see the supposed actual butter knife used by William Shakespeare on Christopher Marlowe (or was it the other way around? Coded references in the erotically charged Sonnet 155 are still debated to this day) at the Buttermere museum in the Lake District quite a few years ago. What is most interesting, apart from the finely filigreed handle, is how its size and form --being much like the length of a household butter knife but with a raised handle-- foretells the current evolution from trowel to what we use today. The knife is displayed on its side, for careful inspection of the engravings and the silver-makers mark on the back. Less appealing is the preserved pad of rancid butter said to also have been discovered. WS & CM inscribed pads of butter are sold in the museum shop, as well as knife facsimiles. The knife was a main feature of Jeannete Winterson's mystery 'Butter is Not the Only Spread'. Elsewhere, the knife used on set in the film of Cat on a Hot Tin Roof recently auctioned in New York in the seven figures.
Speaking of other spreads, it would be remiss of me not to mention the butter knife use with other spreads, both of lower-cholesterol butter imitations and most anything else spreadable such as jams, jellies, marmalades, paté's, Marmites, Nutellas, mayonnaises, soft cheeses, tuna and peanut butter. Public Health and Safety laws as well as some countries and state felony laws require that I note that this is not a recommendation to use any of the above listed spreads on a partner's body for the very common-sense reason of allergic reactions. This much can be appreciated why Winterson's book was banned in this country up until this century.
Personally, I'm affronted by butter knife use in public restaurants. While reusing butter knives can contaminate the butter, all that is needed is to wipe the knife off on an un-buttered area of the skin, or on the leg of your trousers at a push. So the waste of discarded used --and especially plastic-- butter knives really galls me. We've all had the embarrassment of sitting in a booth at TGIF's and your leg dislodging a butter knife that's been stuck under the table.
As noted, it is not necessary to sharpen a butter knife: its lack of a cutting edge is its feature, although we've all become intrigued with the possibilities of gastronomy experimentation we can all agree that the sharper the knife the rougher the skin was in the first place. Polishing a butter knife is essential however, and what better metaphor is it that one strops a butter knife with cotton rather than the leather of a razor strop? You'll find excellent strops down at Marks and Sparks, and even on-line for high-end strops at Agent Provocateur or Ann Summers, although most households still use those well-worn boxers and bloomers passed down through the family. Again, at a push, your trouser leg can be used as well, but only if you are assured of full cotton properties: anything less will stain and corrode.
Finally, I'm quite surprised this nodeshell has been left unfilled for so long (of anyone, I'd've though Rancid_Pickle would've snagged it and written something more prurient during the last IronNoding spree) and would like to thank the ReQuest 2018 crew for the opportunity to node up this essential utensil that has provided a simple service to buttering bodies with, before now, little recognition.