When some one is not able to inhale smoke and struggles with it (i.e coughing and wheezing while smoking)
The main cause of Pussy Lung is a low tolerance to smoke. Pussy Lung can usually be cured by smoking regularly.
Dude 1- "Kyle was hitting the hookah when all of a sudden he started coughing and wheezing and shit, the poor kid almost threw up"
Dude 2- "Looks like hes got a case of Pussy Lung"
Dude 1- "You got that right"