Note 348 — ACT II.
Reading edition
Tickle means uncertain or inconstant. We still use the word ticklish; and a ticklish situation is understood for that state in which we can have no sure dependence. So, in Churchyard's "Challenge," 1593, p. 28—
"Yet climbing up, the tree of tickle trust Wee streache the arme, as farre as reach may goe, Disguis'd with pompe, and pampred up with lust; We gase alof, and never looke belowe, Till hatchet comes, and gives the fauling bloe."
See also Mr Steevens's note on "Measure for Measure," act i. sc. 3.