As a Shia revert, I have noticed that during gatherings at the Hussainia, people often put their hand on their heads when mentioning Imam Mahdi (as) and face the Qibla. What is the significance of this practice?
It is an act of showing respect to our present Imam; Al-Mahdi (AS). We have in our books that Imam Jafar Al-Sadiq (AS) used to do the same when mentioning Imam Al-Mahdi (AS) who is his great grand son and was not born then.When mention our Imam Al-Mahdi (AS), we put our hands on our head out of respect to him being the divine leader of our time.
Wassalam.