I think 90 percent of us played doctor/patient at one time or another ... those who deny are lieing (so the old paraphrased saying goes).
My sister (8 at the time),brother (10) and I (12) did often during the summer when we were off from school and our parents were working. Mom and dad paid me to baby sit when mom went to work from 10 to 3 each day. We found the two bulb syringes mom had and at first just used it as a toy to squirt water at each other. Then we got bolder when my brother said he thought it would be fun to play doctor. Seeing each other naked was not new because until I was about 10, we took baths together.
At first we just inserted the tip a little bit, then all the way, but without water. Then my brother suggested giving each other enemas. We said okay, but agreed everyone had to take one.
First we each took two or three bulbs full. then one time we suggested a contest to see who could take the most of the eight-ounces bulbs. My brother took six, I had five and my sister three.
Our game ended when mom came home from work early one day, caught us in our enema game. She didn't punish us severely, and she didn't tell dad, but she did sit us down and talk to us about the health aspects of sharing the same enema equipment.
Individually, she also talked to us about the dangers of doing what we were doing, obviously in more detail.
We never did our enema games again, but as I think back, it certainly refreshes some fond memories. Through the years, I and my brother and sister got many enemas from mom, but those that we gave to each other seemed to be the most enjoyable.