PENANG hokkien is the most unique.

"Cap Cheng"
direct translation - '10 genes'
actual meaning - *******,
eg: "Ma le lu chao cap cheng, KS limpek hero arh!"
[translation: "WTF, you *******, you ks my hero arh."]

"Kiam Piah"
direct translation - 'salted biscuit'
actual meaning - adult movie
eg. " Ti ti kua kiam piah, bei sian hio?"
[translation: " Always see adult movies, cannot bored?"]