Like Soggy Biscuit.
Last person out of a group of men to masturbate and ejaculate on the Jaffa Cake has to then eat and digest the Sticky Soggy Jaffa Cake.
"Jeff was the last to cum, he now has to eat the soggy Jaffa Cake!"
"...You have to bite through the cream to get to the sticky Jaffa centre..."
Someone who has one protestant and one non-protestant parent. Protestants are often called "orange-men" due to William of Orange and the Orange Order so if you're half an orange-man you're a "Haffa Jaffa" or "Half a Jaffa" as in a Jaffa Cake - an orange flavoured biscuit.
Person A: Did you hear Rory is a Haffa Jaffa?
Person B: Really?
Person A: Yeah, his da's a prod and his ma's a Catholic.