Don't know if you would consider this "sneaking," but my sister and I were into enemas ever since our double-digit years. We were always home from school a couple hours ahead of our parents who both worked, so our enema play was unimpeded. Mom had provided us each with our own enema bags and bulbs, taught us how to self-administer and was fully confident we would use this equipment wisely. Sis and I loved to romp nude when home alone (nothing to do with nudism or naturism, I was first to try this when it just felt so good on a hot summer day after I had showered ... instead of dressing and going on to my next activity, I just walked to my bedroom nude and it felt so good ... so I just stayed nude while in the house. My sister "caught" me, asked why I did that, and I just said, "Try it, you'll like it." That was the beginning of that).
Well, anyway, our enema play began when we administered to each other and it became an ongoing recreation with us ... usually at least once a week, sometimes more ... and we simply enjoyed it.
We sometimes showered together, washed each other thoroughly, but we didn't get into lesbianism, in fact we never even tried it. We're both married, she has a family, we both continue to enjoy "e" sessions with our partners, and we don't get administer to each other anymore ... not that we might not want to, but we're just too busy with our hubbies. it's so much more fun ... if you know what I mean.