Saaib bin Yazid reported,

My maternal aunt took me to the Messenger of Allah ﷺ and said, "Messenger of Allah, my nephew is in pain."He wiped my head and prayed for blessing upon me, then performed ablution, and I drank from the water of his ablution. Then I stood behind his back and looked at his seal between his shoulders, like the egg of a partridge.

Azami 762

Sahih

عن السائب بن يزيد يقول

ذهبت بي خالتي إلى رسول الله ﷺ فقالت: يا رسول الله، إن ابن أخي وجع، فمسح رأسي ودعا لي بالبركة، ثم توضأ فشربت من وضوئه، ثم قمت خلف ظهره فنظرت إلى خاتمه بين كتفيه كزر الحجلة.

الأعظمي 762صحيح
Contents
Reference
Commentary
Ayat
Collection
Jami al-Kamil
Book
Faith
Chapter
Faith in the Prophet ﷺ
Section
Seal of prophethood and its description
Numbering
Jami al-Kamil 762 (2nd edition)
Azami 762