“A term such as flax [in Shakespeare] more or less denotes the object itself; however, upon its use in such a phrase as ‘no more be hid in him than flax,’ it constitutes or institutes a process that weds language to and binds language into culture.
It, therefore, is resymbolized, taking on, in its institution, all of the intricate, intertwined, inextricable connections, associations, references, or allusions that language, now fully specified in its cultural context, must assume.” — From “The Fabric’s the Thing: Literal and Figurative References to Textiles in Selected Plays of William Shakespeare” by Nancy J. Owens and Alan C. Harris
Flax is mentioned in Twelfth Night:
Sir Andrew: “But it becomes me well enough, does’t not?”
Sir Toby Belch: “Excellent; it hangs like flax on a distaff; and I hope to see a housewife take thee between her legs and spin it off.”
Sir Andrew wants Toby’s opinion on his hair, and Toby cracks a sexual joke that refers to flax on a distaff. In the video to the left, you can see a demonstration of how flax is spun on a distaff.
In Shakespeare and Domestic Life, Sandra Clark tells us Sir Toby’s comment puns on ‘take thee’ and ‘spin it off,’ meaning that the housewife (or hussy) will take Sir Andrew sexually and bring him to orgasm).
Clark also tells us some important information about spinning: “To spin was to draw out or twist the fibres of wool or flax into a continuous thread on a distaff. Spinning was a household industry as well as a domestic pastime for women. Spinning and weaving were often regarded as proper activities for the virtuous wife, although the word can be used by Shakespeare with bawdy implications…”
This is some very important context about the time period and how expectations of women and beliefs about their sexuality were tied up in domestic art forms like sewing, embroidery, spinning, and weaving.
And Clarke’s dictionary provides even more context on flax itself:
“Flax is the fibre of the plant Linum usitatissimum, used in the making of linen. Flax fibre was usually yellow in color (hence, ‘flaxen hair’). Flax is associated with the workaday world. Leyontes in Winter’s Tale insults his wife, whom he erroneously believes to be adulterous, by saying that she ‘deserves a name / As rank as any flax-wench that puts to / before her troth-plight,” a flax wench being a woman of the lower class employed in making clothes from flax.” So, Sir Toby Blech’s insult was not only witty—it also signified something about Shakespeare’s world, a world in which being a “flax wench” was could be a codeword for an adulterer.