I think it's just the different words we use for it. I'm fairly certain, remembering back to my childhood, with a brother who liked to visit the joke shop a lot, that whoopie cushions are whoopie cushions, and they all make the same (rear end) type sound. Not sure I've seen any that are more "belchy" than "farty" sounding, if that makes sense.
I'd think a "squeeze a burp" would just be meaning burp instead of fart, so a whoopie cushion...
Ah, the joys of Junie B.!
Lala (2004), and Big Sis 2 (1992)
Grammy to Mr. Boss (2011), Mr. Helper (2012), and Mr. Attached-to-Grammy's-Hip (2014)
All living snuggly together
Big Sis 1 (1991) visiting often!