2. (I don’t know whether it is waham or not) I feel some urine gets on my legs and hips after reflection from toilet seat. And washing these also repeats problem.
3. Please provide the correct way of istinja.
بسم الله الرحمن الرحيم
(1, 2) You should take extra care while doing istinja. However, if sometime urine drops are reflected on to your body after reflection from toilet seat then you should wash them thrice.
إذا أصابت النجاسة البدن يطهر بالغسل ثلاث مرات متواليات؛ لأن العصر متعذر فقام التوالي في الغسل مقام العصر. (المحيط البرهاني في الفقه النعماني 1/200، الناشر: دارالكتب العلمية، بيروت – لبنان)
It should be noted that this ruling shall be applicable only when you are sure or you have strong presumption that impurity has touched your body otherwise it shall not be ruled to wash it merely on the basis of doubt.
(3) The method of istinja is that when a man intends to do istinja etc. he should read dua and put his left foot in the toilet or istinja-khana and he should open his Satr when he is about to sit and while coming out he should put his right foot out and read dua. These are the etiquettes of istinja. One should do istinja while keeping it in mind. It is better if you read Talimul Islam.
Allah knows Best!
Darul Uloom Deoband