This one is almost impossible to describe... One apple asks the other their apple type: "Birs?" (This type is called "quince " in English). But "birs" is similar to "birsz", meaning "Do you like me?" said with a lisp. And the answer is "More than that, I love you", said with a lisp. In short the joke is that the second apple thinks that the first is asking if they like them or not, answering "yesh", signaling that they have a lisp.
A fun concept: Little Red Riding Hood is called "Little Red" in Hungarian, or "Piroska". Vampire is spelled "Vámpír". So combining the two, we get "Vámpíroska"