Feste's song, he sings of a "shroud of white" cloth whose purpose is to cover a dead body. This is in response to Orsino's comments about the spinsters and knitters.

A few lines later, then, the audience still has in mind these previous references when Feste asks that "the tailor" should "make [Orsino's] doublet of changeable taffeta." He is not actually comparing Orsino to taffeta—rather, he is saying that he should have his tailor make his clothing out of taffeta exactly because it is "changeable." Feste's suggestion is that Orsino should display through his clothing exactly what kind of person he is, inasmuch as the simple fabric woven by the spinsters appears exactly as it is.

Feste also states exactly the way in which he thinks Orsino is "changeable." He says that Orsino's "mind is a very opal." So, his opinion of Orsino is that he cannot be relied upon; just as an opal looks a different color from different angles, Orsino changes his mind depending on the context in which one encounters him. Because he is of "such constancy," Feste feels he should be "put to sea" where his "intent" could truly be "everywhere"—that is, because Orsino has no direction and changes his intent continually, he would be well-suited to a life spent upon the sea, allowing it to carry him wherever it would.