"The process starts with a reaction to some sexual stimulus ... experienced as a state of excitement and awareness of [the manifestations of] arousal, such as an increased heart rate," said Dr. John Bancroft, former director of the Kinsey Institute for Sex, Gender and Reproduction.
The eyes dilate, blood flow to the genitalia increases, breathing accelerates, and blood pressure kicks it up a notch.
Why would an unexpected bodily reaction take place alongside this normal physiological chain?
"The brain works as a whole, but is also compartmentalized; it's possible to have a wire crossed," said Dr. Gil Wilshire, a reproductive endocrinologist at Mid-Missouri Reproductive Medicine and Surgery.
"This is how we get things like synesthesia, where people smell colors or see sounds," he said, and this kind of glitch in the brain can lead to strange side effects during arousal and orgasm as the brain becomes flooded with activity.
Arousal can produce compulsive sneezing in some, spontaneous tears for others, he said, and more commonly, women will urinate a bit.
"Some girls call it spending a penny," Wilshire said, referring to the small loss of urine during arousal or orgasm.
Given that the same nerve serves the genital and urinary system, "it's easy to see how one affects the other," Wilshire said.
Michael Castleman, sex educator, counselor and founder of GreatSexAfter40.com, added that "sneezing and crying are the two that are most widely noted. They're just about emotional release and people release emotions differently."
"When it comes to human sexuality and the human sexual arousal response there is a tremendous degree of variation," said Dr. David Greenfield of the Healing Center in West Hartford, Conn. "Although there is a range of behavior that is 'normal' there are many idiosyncratic sexual arousal responses that people have."
As to Seagal's alleged idiosyncrasy, Greenfield "cannot guess what [it] might be," but says that "there are many unique responses that we have that seem unusual and in some cases they are less unusual then we might think."
Waldo said that Nguyen will present her detailed description of Seagal's alleged "unique reaction to arousal" at the trial. No court date has been set at this time.