A person who wants to use the f-slur without actually having the right to use it. They use this fake sexuality to trick people. Being attracted to a character doesn't mean you're a sexuality revolving around that character.
Person 1: What is your sexuality?
Person 2: Dracosexual!
Person 1: Ew! You disgusting pig, that's not a real sexuality! *punches*
Drachenfutter is a gift or some other form of peace offering used by a husband or boyfriend in order to appease an angry woman or girlfriend. Used primarily in cities where there is a significant population of German origin.
Since Jack forgot Madeline's birthday and went out with her older sister, she will punish him by withholding affection until he expresses sufficient repentance with some appropriate drachenfutter.