diddle (v.) Look up diddle at Dictionary.com
"to cheat, swindle," 1806, from dialectal duddle, diddle "to totter" (1630s). Meaning "waste time" is recorded from 1825. Meaning "to have sex with" is from 1879; that of "to masturbate" (especially of women) is from 1950s. More or less unrelated meanings that have gathered around a suggestive sound. Related: Diddled; diddling.