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1.
In short, to fool around with oneself; to masturbate; to commit Onanism.
Preferring toys to men, she diddled Valentine's night away.
by rokesmith February 14, 2005
 
2.
to fool around with someone and do naughty acts to one another
"Did you hear?"
"Hear what?"

"Girl and Boy were diddling in the tent last night!"
by SimplyAmazing December 19, 2009
 
3.
In short, to fool around with someone.
I saw my roomate diddling!!
by ~* JESSICA *~ December 16, 2004