(n.) A severe muscle injury caused by turning one's head quickly to view a well-endowed female.
"That jogger chick had such a nice rack, I almost got titlash looking at her!"
The sudden and violent bouncing motion of the breasts when riding in a schoolbus, particularly when seated over the rear wheel.
"I hate chaperoning these school fieldtrips. I wind up with severe titlash on the bus before we even get there."