(It’s about slang, but there are going to be buttocks, mostly men’s, some startlingly bare, so this posting will not to be everyone’s taste.)
Following up on yesterday’s posting “Buttocks III: (mainstream) art, male art, porn”, Timothy Riddle offered some recently fashionable slang for ‘buttocks’: the M(ass) noun cake, as used by (straight) pornstar Johnny Stone (who has a famously fine ass, and is proud of it, even though it’s not an especially relevant feature in his porn work); and by DC Comics on its Twitter site, showing a photo of the superhero Nightwing (the former Robin / Dick Grayson), played by Brenton Thwaites, who’s also famous for his fine ass, which is much featured on the series.
So: into still more buttocks slang, both M cake and (more commonly) PL C(ount) cakes.