In scuba diving, having reg soup means vomiting into your regulator.

This usually occurs as a result of seasickness, a heavy night out at the dive camp, or a combination of both.

When you make reg soup, your choices are to purge your reg and breath through your own puke for the rest of your dive and hope nobody notices, or switch to your spare reg and look like an idiot in front of your whole dive group.
Dave: Those were some big swells out there. Getting back into the boat was tough.
Steve: I know. Mike had reg soup during the deco stop.
Dave: Ha ha! What a chop!
by George McBob April 29, 2009
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