A chain reaction of vomiting (often at sea or during travel), usually caused by the smell of vomit, similar to a Mexican Wave.
While returning from a night of heaving drinking after an England game in France, the hovercraft started to bounce around, causing a fan to vomit. As the smell reaches the next person it makes them vomit, and so on.

Common reaction: oh fuck, look out, it's a Mexican heave & it's heading our way!
by Alfonse Le'ver June 1, 2011
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