What are the obligatory organs to wash when performing istinja', and is it sufficient to wash only the urinary meatus, or is it obligatory to wash the entire penis and the pubic hair area?

Istinja’ (purification after defecating or urinating) is obligatory by removing impurities with water or purifying agents if feces or urine are discharged. However, if it is merely gas, istinja’ is not required. When urinating, the head of the penis should be washed, and for defecation, the anus and the surrounding area affected by the impurity should be washed. If urine or feces extends beyond their original place, that area should also be washed.

Among the etiquettes of relieving oneself: 1. Saying "Bismillah" and then: "Allahumma inni a'udhu bika min al-khubuthi wal-khaba'ith" (O Allah, I seek refuge in You from male and female evil spirits) upon entering the lavatory. 2. Entering with the left foot first and exiting with the right foot first. 3. Distancing oneself when relieving oneself in un designated areas. 4. Not facing or turning one's back to the Qiblah. 5. Being careful to avoid urine splashes. 6. Not touching the penis with the right hand while urinating. 7. Not relieving oneself in people's pathways or shaded areas. 8. It is disliked to speak while relieving oneself. 9. Saying "Ghufranak" (I seek Your forgiveness) upon exiting the lavatory.