A 'dead calm' is the action following someone having an uncontrollable sex urge during a very intense sex scene in a movie. The result is to promptly go to the bathroom or other private area to masturbate. Both applicable for women and men.
The reference to dead calm, is from the 1989 movie by that name. A very intense sex scene that has made many people have a sex trigger.
If this sex scene continue intensifying, I will probably have a 'dead calm' moment
Do you know where he went? Been a long time to the bathroom, he probably did a 'dead calm' on us after this porn clip.