transitive. To tickle (in physical sense).

To touch or stroke lightly with or as with the finger-tips, a straw, a feather, a hair, or the like; to tease, annoy, or irritate lightly, so as…

transitive. To touch lightly; to irritate slightly; to tickle. Also intransitive.

Of persons: To tickle or titillate.

transitive and intransitive. To tickle (in various senses). Cf. tittle, v.2

slang. To poke, tickle, etc., (a person) in a sensitive part, esp. the genital or anal regions; sometimes, more specifically, = fuck, v. 1.