I started self-administration about the age of ten, and continued for the next forty years, developing my own equipment from my work in laboratories. In my teens it was difficult to keep a plain rubber Jacques cathether in place, and zinc oxide adhesive tape didn't help much, and was a distraction. Then about 17 I discovered Foley catheters with small balloons - 10 to 20 mls. These were a great help until in my mid-twenties I was introduced to the large balloon catheters for barium radiographs. These cost the earth, and occasionally burst, but the sensation of the balloon being inflated, relentlessly, especially by Sr Veal - who some of you may have met - is astonishingly moving. She'd learnt about them when she worked in America at the Sherema Clinic.
Now these large inflatable balloon catheters are often made of silicone rubber, I believe.
The latex ones could safely be inflated to the size of a tennis ball, and sometimes could be blown up to a Seville orange size without bursting.
As a peripubertal lad, I found the traditional jug with a Higginson's syringe awkward to use - the inlet end often came out of the water and so air got sucked in too. So the inlet tubing required lengthening with a piece of rubber tube, the end of which was weighted down with a piece of lead tubing, or a large steel nut. The bowl or jug was also a hazard in the bathroom, which occasionally got flooded with soapy water, so I found a rubber bung fitted with a short bit of 8mm glass tubing could be fitted into the screw neck of an ordinary hot water bottle. This had the added joy of being able to sit on the hot hot-water-bottle which also considerably increased the force of the inflow. It still leaked a little, but was a grand improvement until I found the real McCoy at university. This was a black plastic tubing adaptor which screwed into a hotwater bottle and made a watertight fit, especially if it had a rubber washer to make the seal really tight. They were sold to convert the hot water bottles into douche bags, known in the US as "fountain syringes".
I prefer to reserve the name "syringe" for things which pump - the classic being the Victorian rubber Higginson's syringe. There were two at home which my mother used for douching, I believe, and these had a short 6" vaginal pipe of hard but flexible rubber. These intrigued me for they had four perforations each about 1.5 mm diameter, arranged at right-angles to each other, near the tip. This was preferable to a plain black Bakelite nozzle with a 3mm opening at the tip, or a piece of blunt-ended laboratory rubber tube which had sharp edges and frequently got blocked at the end. I found I could model a conical tip to these using Copydex. This was a white latex adhesive which I could coagulate satisfactorily with strong sulfuric acid, from the school lab.
So I became an expert in home-made rubber technology by the age of 16.
But enemata in my bedroom were more satisfactory than in the bathroom. The carpet was more comfortable than lino, and one could admire the view with a strategically placed mirror. This was most comfortable in the left-lateral position with my knees drawn up to my chest, and my head resting on a pillow.
Then about the age of seventeen I discovered that ether could be administered p.r. But that's another story.