Is the water that comes out of the penis considered impure and does it invalidate ablution if it enters the penis during Istinja'? And is it better to sprinkle water on the private parts after Istinja'?

If water enters the male organ and then exits, it is considered impure (najis) and invalidates ablution (wudu), due to the impure wetness it carries. One must be cautious not to give in to the whisperings (waswas) of water entering if it did not actually happen, as it might merely be pure residue after Istinja' (cleansing after relieving oneself). It is recommended to sprinkle water on the private parts and trousers for those who suffer from whisperings regarding purity, in order to cut them off.