What is the ruling on prolonged stay in the bathroom in an attempt to expel remaining drops of urine after natural urination, and the consequent missing of some prayers?

Scholars have differed on the ruling regarding shaking and milking the penis to expel urine. Some, like Shaykh al-Islam Ibn Taymiyyah, consider it impermissible, arguing that it was not narrated from the Prophet (peace be upon him) nor from the Companions, and that the penis is like a breast: if milked, it produces, and if left alone, it dries up. He further holds that shaking and squeezing lead to waswasa (whispers of the devil/obsessive thoughts). Others, like Imam al-Nawawi, consider light shaking, squeezing, and clearing the throat to be recommended, provided that this does not lead to waswasa. To cure waswasa, it is advised to relieve oneself, cleanse, and perform ablution without paying attention to doubts. One can also sprinkle water on the trousers after cleansing to repel waswasa.