My dad is one of the bartenders at our local Deaf Club (in fact, he runs the bar). If you ask for for a Coke, you get asked (in sign language, obviously) “Fat coke or thin coke?”. That always cracks me up.
“I think I’ll have fat coke for fat people, please! And while you’re at it, I’d like a side of lard!”
I’ve never quite worked out whether “fat coke” is generally recognised slang for non-diet coke. I’ve heard a couple of people use the phrase, and they did so in an off-hand manner, suggesting that it was common parlance. Perhaps they picked it up from deaf people, because it was new to me and I have since tried it out a couple of times, only to be met with blank looks all round until I explained it. Maybe I just hang out with stupid people.