The narrator is describing how he almost choked on cheese pudding…
Ego denique vespera, dum polentae caseatae modico secus offulam grandiorem in convivas aemulus contruncare gestio, mollitie cibi glutinosi faucibus inhaerentis et meacula spiritus distinentis minimo minus interii:..
In my case, eveningtime, while I ventured, after the manner of my dinner companions, to scoff a slightly larger piece of cheese pudding and the soft food clung to my throat with my passages of breathing constricted, I just about did not die.
This is a somewhat idiomatic translation. I’m particularly interested in:
modico secus. I’m taking it that this refers to the fact that he was eating a slightly larger piece of cheese pudding in competition with his companions..
meacula spiritus distinentis - literally the passages / airways of constricted breath (?)
Apuleius is hard! I too was puzzled by modico secus, evidently to be construed with grandiorem. The OLD compares paulo simillimum (again Apuleius!), “as near as makes no difference, not far off,” and takes modico secus to mean (“app[arently]”) “somewhat, a bit.” (Or could it mean a whole lot bigger? I don’t really know how Apuleius uses secus.) Modico will be abl. of “measure of difference.”
Same with minimo minus interii below, “I less died by the least amount possible,” i.e. I came within a nanometer of dying.