My question is regarding purification (Tahara) after passing stools. The Sunnah tells us to use three stones (or their equivalent) or a small container of water (e.g. a jug) and that this is enough. However I have immense troubles and please forgive my detailed question, as there is no shame in religion .As you know the anus (or anal sphincter) is not a hard object but is made of muscles. Many times when I start washing I feel that the anus has relaxed a little and so exposing an unclean area that needs to clean so I have to start washing again. Or sometimes, after I start washing, and particularly if I am tense the anus contracts and so covers an area that I was trying to wash and I have to make an effort to make the anus relax so as to expose that area again so that I am able to reach it. Also there is an indentation just behind the anal ring which cause me the same problem as that indentation becomes wider or narrower depending on the state of the anal sphincter). This causes me immense difficulties as I spend a longer time washing than most people I know and I use lots of water (9-12 litters and maybe more) and it is difficult when I do not have a hose to put to a tap.Also, I worry about the water from the washing splashing in the toilet bowel and reaching me as I am sitting on the toilet. The result of that is that I have to wash myself at least from the waist down every time I go for defecation. I feel that it is so hard just to do my daily activities.Please tell me what is required after defecation (passing stools) Once again I cannot thank you enough.

Praise be to Allah, the Lord of the World; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

Allah has not laid upon you in religion any hardship. It is sufficient for you while cleaning yourself after answering the call of nature to remove the impurity with a stone or anything that can remove it such as tissues and the like. After that the remnants are not taken into consideration since, using a stone does not eradicate the impurity even though the Shari'a accepts it.
If you clean yourself by water that is better, and then removing the moistness or the fecal matter is sufficient.
One should not bother oneself about washing what is hidden from the private parts; it is from among innovations and Devilish insinuations. It is sufficient to clean what is possible in the position of relieving oneself.
Allah knows best.