Fear of male sexual excrement that goes beyond fear of spitting/swallowing. One suffering from cumaphobia usually substantiates her fear by delivering meaingless threats such as "If your cum comes anywhere near my face I will wipe it on your shirt."
These threats are worthless because those suffering from cumaphobia fail to realize that a messy shirt is worth a shot in the face.
"As I was about to cum, my girlfriendfreaked out. Realizing that she suffered from cumaphobia, I helped her face her fear by shooting a load all over her face."
A rare mutation of Mephobia (Fear of becoming so awesome that the human racecan't handle it and everybody dies.), where the phobia appears in two or more first cousins almost simultaneously.
Cure - There is none.
Cousin1: "Cousin, we have a problem. I have just diagnosed myself with Cuzphobia and you're the nearest cousin which means..."
Cousin2: "NO! Now we'll never find someone as awesome as us!"