is when, just before or in the middle of sex, a person has a panic attack, starts crying, or runs out of the room naked because of nonsensical emotional distress (a person who is upset because they are being hurt/forced/etc does not count, only if they want the sex and panic because they are about to get it).
This act is referred as "pulling a dwayne". Somewhat offensive term.
Two people who have had a crush on each other for months finally get in bed. He gets naked, she's almost so. As he's pulling off her underwear, he begins hyperventilating, then runs out of the room naked saying "I'm sorry I'm sorry!" and then spends an hour crying in the shower, leaving her laying there wondering "wtf? Is he pulling a dwayne?"