fescue, n. — Green’s Dictionary of Slang

fescue n.

[SE fescue, ‘a small stick, pin, etc. used for pointing out the letters to children learning to read; a pointer’ (OED)]

the penis.

1613–16		Fletcher Two Noble Kinsmen II ii: Do but put / A feskue in her fist, and you shall see her / Take a new lesson out, and be a good wench.
1641		J. Johnson Academy of Love 99: The young sparkish Girles would read in Shakespeare day and night, so that they would open the Booke or Tome, and the men with a Fescue in their hands should point to the Verse.
1672–96		‘Will the Merry Weaver’ in Pepys Ballads (1987) III 132: I gave her a Fescue in her hand, And bid her use it her command. She said you best know where it should be, Come put it to my A.B.C.
1710		J. Dunton Athenianism II 263: [A] night walker ... half eat with the pox [...] too abominable to be touch’d with any thing but a Pair of Tongs, or a Fescue.
1748–49		Cleland Memoirs of a Woman of Pleasure (1985) 73: I guided gently with my hand, this furious fescue, to where my young novice was now to be taught his first lesson of pleasure.