I can only speak from a receiving perspective. but none of the three scenarios from the OP hit all the notes to make a chord that moves me.
To me, the power of enema is in experiencing the often unspoken elements: the shy, taboo, embarrassing, humiliating, degrading, helpless, controlled, etc. elements.
The Top knowing what they want, but being a little unsure about being able to get it, yet pursuing it all the same with a little vulnerability, risk taking... with confidence that grows as part of the dance, from the response of the bottom. For me, the most powerful element during the dance is when both experience the connecting of mutual desire, despite (and because of?) all the above feelings.
To me, delicate, nuanced control is a lot more powerful than brute, or otherwise, force (again, "to me," not making this a universal assessment). Them whispering in my ear that they'd like to give me an enema, a combination of expressed, vulnerable desire, almost asking permission, but based on suspicion that i'd want, maybe need, to submit.....