Touch (a body part) lightly so as to excite the surface nerves and cause uneasiness, laughter, or spasmodic movements.

synonyms: tickle, titillate.

Roget 315: be agitated &c.; shake; tremble, tremble like an aspen leaf; quiver, quaver, quake, shiver, twitter, twire^†, writhe, toss, shuffle, tumble, stagger, bob, reel, sway, wag, waggle; wriggle, wriggle like an eel; dance, stumble, shamble, flounder, totter, flounce, flop, curvet, prance, cavort [U.S.]; squirm.    throb, pulsate, beat, palpitate, go pitapat; flutter, flitter, flicker, bicker; bustle.    ferment, effervesce, foam; boil, boil over; bubble up; simmer.    toss about, jump about; jump like a parched pea; shake like an aspen leaf; shake to its center, shake to its foundations; be the sport of the winds and waves; reel to and fro like a drunken man; move from post to pillar and from pillar to move from post to pillar and from pillar to post, drive from post to pillar and from pillar to drive from post to pillar and from pillar to post, keep between hawk and buzzard.    agitate, shake, convulse, toss, tumble, bandy, wield, brandish, flap, flourish, whisk, jerk, hitch, jolt; jog, joggle, jostle, buffet, hustle, disturb, stir, shake up, churn, jounce, wallop, whip, vellicate^†.    ... show more

Irritate as if by a nip, pinch, or tear:
— Smooth surfaces can vellicate the teeth.

synonym: pinch.