Can You Pray Witr Twice?
Question

I want to ask whether at the end of Tarawih prayer we should pray Ash-Shaf’ [two Rak`ahs of Nafl prayer] and Witr.
I heard that the last prayer you pray should be Witr. Does that mean that if I get up to pray Qiyam Al-layl I should pray Ash-Shaf` and Witr again, or should I delay them until I pray Qiyam and then pray it?
Praise be to Allah.If the Muslim prays Witr then he wants to pray Qiyam Al-layl after that, he should pray them two by two, and he does not have to repeat Witr . 
The Prophet (peace and blessings of Allah be upon him) commanded that the last prayer offered at night should be Witr , but this command is in the sense that is it recommended, not obligatory
Shaykh Ibn Baz (may Allah have mercy on him) was asked: 
If I have prayed Witr at the beginning of the night, then I get up to pray Qiyam at the end of the night, how should I pray? 
He replied: 
“If you have prayed Witr at the beginning of the night then Allah enables you to get up at the end of the night, then pray whatever you can two by two – without Witr , because the Prophet (peace and blessings of Allah be upon him) said: “There cannot be no two Witrs in one night .” 
And it was narrated from `Aishah (may Allah be pleased with her) that the Prophet (peace and blessings of Allah be upon him) used to pray two Rak`ahs after Witr sitting down. The reason for that – and Allah knows best – was to show the people that it is permissible to pray after Witr .” (Majmu` Fatawa Ash-Shaykh Ibn Baz, 11/311) 
And Allah knows best.