A mureed asked this question.
Sayyidi wa sanadi Hazrat Mawlana Mohammad Taqi Usmani (Allah SWT preserve him and allow us to benefit from him abundantly. Ameen!) replied:
“If the Sheikh is talking one should whole heartedly concentrate on listening.
If he is silent or busy in some thing one can read, recite or complete his wird, etc.”
On being questioned further regarding the classical tasawwuf teaching that a mureed must sit in Sheikh’s presence with the muraqabah (concentrated thinking) that anwar & fayuz (enlightening blessings) emanating from Sheikh’s qalb (heart) are coming into my heart.
Hazrat db replied; “Yes! As per our pious elders this muraqabah is beneficial.
Although my heart is empty but by the barakah of a true seeker Allah SWT may enlighten it.”