A play on words, and joke version of asperger's syndrome. Used as the title of the South Park episode Ass Burgers, S15 E8.
Nurse Bronski: Why are there hamburgers in your underwear?
Cartman: Are you serious? How can there be- Oh my God! You're saying I have ass burgers??
Nurse Bronski: This doesn't make sense. Are you trying to sneak food into the school or something?
Cartman: What are you talking about?? I got vaccinated from the school, and now clearly I have Assburgers!
Nurse Bronski: Very funny!
Cartman: Well I'm glad you think Assburgers is funny! Just note my condition on your records there!
Nurse Bronski: Get out of my office!