What was the first object slid into your rectum?

I can't really remember. Probably either a rectal thermometer or a children's suppository. I'm a child of the '50s and RT, suppositories, and enemas were mom's stock in trade.

Thermometer and probably a suppository

A enema nozzle when I was in the hospital at 13 for appendicitis, I was hooked there after. 😉

A handle of a small mirror that was held with two fingers. It was smooth plastic with rounded sides and 1/4 inch thick and 1/2 inch wide and 2 inches long. It didn’t hurt and it felt so good because my eleven year old bud was very tight.

A douche spray tube. It felt really good as a teen ager

As others have said...when young an infant thermometer.

When a consenting adult...my sub's lubed finger

My finger

I was 7 years old and I put a Q-tip up there. From that point on I was well on my way to being an anal erotic and I'll tell you it feels pretty good