Green’s Dictionary of Slang

(Aus.) a penis, usu. a child’s penis.

1967		J. Hibberd White with Wire Wheels (1973) 158: simon: Perhaps they’re about to descend. mal: (in a high-pitched voice) There’s nothing wrong with my tossle.
1982		N. Keesing Lily on the Dustbin 47: Those of the Dr Spock generation consciously scorned old-fashioned usages [...] A penis was called a penis and not a ‘tossle’ or a ‘doodle.’.
1999		G. Seal Lingo 88: The extent and variety of the Lingo terms for genitals and other body areas hints at a determined, if perverse, use of euphemism to avoid the use of perfectly respectable words like testicles, penis, vagina, and posterior. Such terms, though, seem sterile and colourless to the Lingoist who prefers such delights as [...] prick, dick, old fella, tossel, stalk, throbbing gristle, trouser snake.