Purity: Recommended Precaution for Performing Tayammum

Practical Laws of Islam as per the teachings of Ayatullah Sistani

Ruling 690:

The recommended precaution is that tayammum – whether it be in place of wuḍūʾ or ghusl – should be performed in this manner:

(1) the palms are struck on the ground once and wiped over the forehead and the back of the hands; and

(2) they are then struck again on the ground and wiped over the back of the hands.

-Ayatullah Sistani, Practical Laws of Islam, Purification (Taharah)