Question 9: Should the voluntary Sawm (Fast) of the six days of Shawwaal be observed directly after Ramadaan, following the day of `Eed-ul-Fitr (the Festival of Breaking the Fast), or is it permissible to start observing it several days after `Eed-ul-Fitr, during the month of Shawwaal?
Answer: It is not necessary to observe this Sawm directly after `Eed-ul-Fitr. It is permissible to start observing it one or more days afterwards. The six days can be observed either consecutively or non-consecutively during the month of Shawwaal, whichever is easier. This matter is open to choice, as this Sawm is Sunnah and not Fareedah (obligatory act)... read more here.