False self-diagnosis of High-functioning Autism (asperger's syndrome), mostly used by nerds with no social skills as an excuse for the complete failure to understand irony in real life.
Might also refer to a slightly autistic person with a nice ass
Assburgers was mentioned in southpark first S15 E8.
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 Syndrome is funny! Just note my condition on your records there!