In fasting the six days of Shawwal, is it necessary that the days be consecutive or is there no harm in fasting them separately (spread out) during the month?
Fasting six days of Shawwal is a confirmed Sunnah from the Messanger of Allah-Sallallahu alaihi wasallam. It is permissible to fast them consecutively and separately. This is because the Messanger- Sallallahu alaihi wasallam- mentioned their fast unrestrictedly and he did not mention that they should be done consecutively or separated. This was when he said: Whoever fasts Ramadhan, and then follows it up with six (days of fasting) from Shawwal, then that is as if he fasted the entire time(i.e.,year) This was recorded by Imam Muslim in his Sahih. And success is from Allah.
1.Muslim no. 1164.
Shaykh `Abdul-`Azeez Bin Baz
Fatawa Islamiyah Page no. 335 Vol: 2