Don't know that they do!!
I'm satisfied with what IS available.
Never modified anything. Never needed to!
Always able to find what I want.
My father haf to do something EXACTLY ONCE
when he was growing up, his mother was EXTREMELY anti-enema, at least for boys, and she never had a daughter who made it past 18 months.
She DID have a combination bag that she bought in the 1950s right after she immigrated from Germany. She used it mostly to douche, at a time when many doctors were still encouraging it.
When Dad found the bag in the linen closet, and could finally get to it, he immediately realized what the rectal tube was for and started experimenting with it.
Once his Mom realized what was going on, she hid, and later destroyed the rectal applicator, Dad was too scared to try the douche nozzle, so using an Exacto knife and a candle, he was able to take apart a Bic "Stick" type pen and craft a fully functional rectal nozzle out of that Bic pen. He used it until he was in hes early 'teens, had an afternoon paper route and was generating his own money Spent some of that money and a summer morning riding his bike several miles along a busy highway to get to a large-format drug store, where he bought his first bag!!