Cantonese mouth looks like honey.

Putting honey on your mouth and putting oil on your mouth are expressions and meanings in two different contexts.

Mouth as honey, Cantonese: so sweet or really sweet. Here is purely a description of "sweet mouth" without "smooth tongue".

Cantonese is eloquent, which means that Mandarin is eloquent.

The literal interpretation of these two sentences is that "smearing honey" is sweet; "Wave oil" is slippery. If it is used to describe both, it is called sweet mouth and slippery tongue. Speak cantonese; Put your mouth like wave oil, which makes people happy.

Note: "Wave" oil passing is an exaggerated description of washing the nozzle with oil (slippery enough).