A dirty, sweaty vagina that is potentially also moistened by arousal but not always. Swampvag usually occurs in girls who haven't showered or had sex and didn't clean up afterward. It's most noticeable in rooms with little to no ventilation and on hot days.
"It smells like fish and BO in here, what is that!?!?"
"I think that girl has swampvag..."
When a driver (a middle aged or older woman named Gail) is getting too close for comfort behind another on the road. When the driver hits you, she will arrogantly assume she did nothing wrong as if Gailtating isn't illegal or dangerous.
Innocent driver: WTF, this bitch won't get off my ass!!
Passenger: Fuck, someone's Gailtating you again, switch lanes before she rams you at the red light.