A Dum-Dum is that stuffed animal that you always will keep with you until you die because you are a grown man that still lives in his parents basement that has nothing else to do in their life.
John- Yo Bob why do you still have that stuffed animal from when you where a kid, your like 36 years old?
Bob- Oh that, that's just the Dum-Dum I still have because I have nothing to do in my life accept eat Oreos and play video games in my parents basement. Why?
John- I don't know, just asking.