Hadith.3201 - When you arrive at the Euphrates River, perform ghusl (ritual purification), wear your two pure garments, and then proceed to the grave. Say:
"May Allah’s (swt) blessings be upon you, O Aba Abdillah.
May Allah’s (swt) blessings be upon you, O Aba Abdillah.
May Allah’s (swt) blessings be upon you, O Aba Abdillah."
With this, your visitation is complete under the condition of taqiyya (precautionary dissimulation).
This was narrated by Yunus ibn Zabyan from Imam Jafar ibn Muhammad Al-Sadiq (as).