It is a terminus which defines the psychological disease which makes a boy who's really often horney but don't show it that much, that he thinks that he would get the cutes and hottest girl exist or he knows. The problem is, the mens that got this "p.d." are more like not good looking in the eyes of the women.
Person A: "Oh man, look at this girl , she's so cute and looks super sexy"
Person B: "You won't get the girl in 100 ages, you should do sth against your Morbus Gerutius".