When a person has so much swag that it interferes with their day to day life.
Symptoms range in severity and include (but are not limited to): incessant attention from members of the opposite sex, losing friends to jealousy, swollen pockets, an insufficient availability of contact entries in one's phone, and being discriminated against due to swag levels.
The causes of this new epidemic are not well established, but preliminary findings suggest that there may be a positive correlation between being raised in an inner city black neighborhood and the likelihood of developing this disorder.
Joe: The FAA pressed charges against him for being too fly.
Josh: Dang, sounds like a bad case of TMSS...