As for the requirement to pray two units after every seven circuits, this is established by the practice of the Messenger (may Allah bless him and grant him peace).

Nāfi said: “Ibn Umar (may Allah be pleased with him and his father) would pray two units after every set of seven circuits.” Al-Bukhārī cited it as a suspended report. (1)

Ismā‘īl ibn Umayya said: “I asked al-Zuhrī, ‘Atā says that an obligatory prayer suffices in place of the two units following circumambulation. Is that so?’ He replied, ‘Following the Sunnah is better. The Prophet (may Allah bless him and grant him peace) never completed a set of seven circuits without praying two units.’” Al-Bukhārī cited it as a suspended report. (2)

– (2-17-4) Where Should They Be Performed?

After circumambulating the Kaaba, the Muslim prays the two units following circumambulation behind the Station. If that is difficult, he may pray them wherever he wishes within the Sacred Precinct.

The following evidence establishes this:

The words of Allah, Exalted is He: “And take the Station of Abraham as a place of prayer.” [al-Baqara: 125]

Humayd ibn Abd al-Rahmān ibn Awf reported that Abd al-Rahmān ibn Abd al-Qārī told him: “I circumambulated the House with Umar ibn al-Khattāb after the dawn prayer. When Umar completed his circumambulation, he looked and saw that the sun had not yet risen. He therefore rode on until he dismounted at Dhū Tuwā, and prayed