From the book series Dune. It's a sign that a large sandworm is approaching. Can be used in any situation where one is asking if something is approaching.
Stilgar, do we have wormsign?
When you can see an erection through someones pants. Normally occurs during foreplay or while making out. Sometimes it occurs when a male thinks about a women in an erotic way.
Ex. A Girl turns to her boyfriend/husband after some foreplay and she asks "Do we have WormSign." and his reply is "We have WormSign the likes god has never seen."