Green’s Dictionary of Slang

gutta-percha n.2

[the use of gutta-percha leaf as a covering]

(US) the foreskin.

[US] in Randolph & Legman Ozark Folksongs and Folklore (1992) I 113: ‘An’ all he could do was to fiddle, fuck an’ dance. / With his great big tilly-whacker, great big kidney-cracker, / Yard of gutta percha, a-hangin’ to his knees.’.