What is the correct method for Istibra' from urine, and does the exit of urine drops after Istibra' invalidate purification?

A Muslim must purify himself from urine by waiting a moment after it stops, or by coughing, or by taking a few steps, then performing istinja (definition) (washing). If he performs istinja immediately after it stops, his purification is valid unless he is certain something has come out. Whatever urine has spread outside the exit must be washed. If it has not spread, wiping with a stone or tissue is sufficient. It is best to combine wiping and water. Then, the private parts and clothes should be sprinkled with water after istibra (ensuring no more urine will come out) to put an end to whispering doubts (waswasah).