There is more than one aspect of this excitement.
First, it is the serious deep intimacy of giving each other an enema. How much closer can you get to a person that pouring something into their entrails? And when you do it to each other, that's a bond of excitement almost nothing can match. And then there is the butt plug or the inflation bulb to keep it all in.
Secondly, you know that you have limited time before an explosion will occur. So you have an urgency to please and get pleasure before the pressure becomes unbearable. So you use all your best tricks on each other to produce the most sensations in the shortest time - just in case one of us has to break off.
Finally, the sensations in your bodies are different. It will depend on the size of the enema and we use a 4-quart [one gallon] bag, which we share through two tubes and nozzles simultaneously. Who knows how much we each take? It doesn't matter - we just share it. Until the bag is empty. Sometimes I hoist it higher and higher until it empties against our internal pressures. Then her abdomen is taut and so is mine. And the butt plug or, in her case, the inflated bulb. Her vagina is moist and tightened. My erection is stiffened. And we simply go to it.
Quickly as possible we romp around until we both reach a climax. And then dash off to the bathroom. Always her first.
Occasionally, we've had accidents and one or both of us has pushed out our plugs. Then what a mess. And we've learned to have a big water-proof sheet under a thick beach towel, just in case we get it wrong again. It happens when the excitement and the orgasms last longer than usual. Like I said, messy when it happens, but not unpleasant for seasoned lovers and erotic in its own way.
We wonder if we're unusual in this. Does anyone else have similar experiences?