Something used to insulate a drinker's hand from a handleless cup. (from the Arabic word ظرف ẓarf)
Traditionally - an ornamental metal sleeve and ring that would hold a porcelain cup. In modern times, it's the little cardboard sleeve they put around your cup of coffee at Starbucks.
"Jesus, Katie, this coffee is hot. Didn't you grab a zaddledoo?!"
Sorry bro, i just fadoodled all over you shirt.
What the heck bro! You just spit all over me!
Sorry man, i'm such a fadoodler!
Why did you just fadoodle on my shirt?
I didn't mean to chuck fOod on you, my bad.