PCA (Phantom Cock in Ass) Syndrome, the constant feeling of another man's cock in your ass when none is present. Generally, PCA occurs in closet homosexuals that have yet to fully identify themselves as being gay due to the concealment of their true nature. Some of the more severe cases of PCA can lead to bowel leakage and involuntary excretions.
Those with PCA often equate their problem to those with disambiguation or "Phantom Limb Syndrome". The intense sensation that your limb is still present.
"This cool dude I know came over and we played xbox in our boxers".
"Damn, my ass hurts".
"I feel like I have to shit a lot".
"I just took a huge shit but it feels like I have to go again".