Absolutely YES! Mom and Grandma started increasing Sis's and my capacities from early childhood. They started us in infancy with a four ounce bulb, with more bulbsful added over time, until we were taking a two qt bag. They continued by emptying the bag into us, then adding eleven ounce bulbs until we were easily taking three quarts. From there, they bought us four quart bags, and we received four from that time forward.
When we realized we wanted enemas, and started giving to each other, Sis wanted to see if we could take more and from about twelve years until we left home, we slowly increased until I could easily take six quarts, and Sis could take eight. Now that we live together, and cannot move our bowels without help, we usually start each day with a four quart Ivory SSE and a five or six quart rinse.
Of course, when engaging in enemas for sexual reasons, we both take eight. Neither of us think our enemas caused dependence, but rather the nightly bedtime doses of Fletcher's Castoria, and later Sennalax stripped us of our ability to poop by about age ten. Sis is older, so she was first. We didn't really care, because the twice weekly enemas and nightly laxatives kept us from becoming uncomfortably constipated.
Somewhere around ten, Grandma started inserting a suppository in us before breakfast on weekends. We both loved the feelings of the insertion, but not the cramps. We enjoyed them so much that Sis bought a jar of 100, and we would sneak them whenever we could find an opportunity. They were wasted, because we would expel them before they started working. We both enjoyed that process, too.