What is the proper way to space out pregnancies for the purpose of breastfeeding for two years?

Islamic Sharia (definition) encourages large families and considers it a blessing, as Allah Almighty says: "And Allah has made for you from yourselves mates and has made for you from your mates children and grandchildren." And as the Prophet, peace and blessings be upon him, said: "Marry the affectionate, prolific woman, for I will boast of your numbers before the nations." If a family needs to regulate pregnancy and breastfeeding, there is no objection to using permissible means such as coitus interruptus ('azl) and non-harmful medications.