How does drinking carbonated beverages or alcohol cause hiccups?

So I understand that hiccups are caused by the spasmodic contraction of the lungs causing a sudden rush of air in turn causing the epiglottis to cut off air flow thereby making the hiccup sound. And I understand that the contraction of the lungs is caused by irritation to the phrenic and vagus nerves. But what I want to know is how drinking stuff can cause irritation to said nerves. Can someone please be my savior and give me an answer?