Oddest and certainly most memorable was a loaf of frozen bread dough.
It was about 3 inches in diameter and about 8 inches long, and was the kind that rises as it thaws. I had spent the day making my rear submit to deep 10 inch dildo fucking alternated by huge butt plugs held in with a diaper—I was out of kinks, but wanted more. I packed my butt with most of a jar of vaseline, used the rest of it to slather the dough. It slipped easily past my relaxed sphincter, and with a bit of difficulty (it wasn’t flexible like my dildo), got it deep enough to close my back door. I promptly wrapped myself in a tight, thickly layered diaper, and began my most memorable anal experience.
The first fifteen minutes or so were difficult. The loaf itself started out as somewhat too big for the space it was in, and rock-hard, so very uncomfortable. The presence of what basically amounts to a huge ice cube in my belly dropped my body temp, making me feel a chill, but not alarmingly so. While I endured this, I got myself into a fantasy head-space to suit my predicament. I was an adult, but not in control, and was humiliated by being bound, diapered and treated like an incontinent infant, and desperately wanted to avoid “messing” in my diapers, which would guarantee further humiliating treatment.
As the dough thawed, it rose. The dough expanded in my rectum, and the CO2 given off by the yeast tingled my gut. Soon the pressure became too much, and I lost control. An impossibly huge mass slipped out and stretched my diaper. I thought I was done, but for the next hour I occasionally passed masses of dough, without warning or control. Then, I had dough-scented gas for hours. The physical sensations were amazing, and I enjoyed a fantasy of forced incontinence without the turn-off of scat.