Not doing tawaaf al-ifaadah

Shaykh Ibn ‘Uthaymeen said: 

Tawaaf al-ifaadah is one of the pillars (essential parts) of Hajj without which Hajj is not complete. If a person does not do it, then his Hajj is not complete, and he has to do it, so he has to go back – even from his own country – and do tawaaf al-ifaadah. In this situation, so long as he has not done tawaaf al-ifaadah, it is not permissible for him to be intimate with his wife, because he has not fully exited ihraam, because one does not fully exit ihraam (the second stage of exiting ihraam) until after doing tawaaf al-ifaadah and saa’i, if he was doing Hajj tamattu’ or qiraan and he did not do saa’i along with the tawaaf of arrival (tawaaf al-qudoom).