You can say ning nong, but not ding dong. Ding Dong means stupid, crazy.
I couldn't find any meaning in the Lao and Thai dictionaries of the words Ding-Dong, and how the heck did you know that the words Ding-Dong mean Stupid and Crazy !!!!!!. when people label or comment about sombody Ding-Dong it' doesn't mean he/she is crazy or stupid... Don't follow the crown it will make you look stupid.
I was having a thai massage in Bangkok airport and the girl massaging me started laughing after the girl in the next cubicle said something in Thai. I asked her what was funny . She said her friend just had a "ding dong". I assumed it was a sex based comment from the laughter but after reading here perhaps the guy was just nuts.
Okay, just to clarify things. The word "Ting Tong" (which might be misheard as ding dong) means someone who is a fool or crazy in a stupid way. The phrase "ning nong" is not a Thai or Lao phrase, at least one I've ever heard a Thai or Laotian speak. And it is the phrase "aeb baew" which means cute, and "baw" which means crazy. Lastly, Thai and Lao are certainly not the same.