Fiqh-us-Sunnah Volume 5, Hajj and ‘Umrah, Fiqh 5.076A.

It is reported by Ibn ‘Abbas that the Prophet (peace be upon him) and his companions declared their intention to perform ‘Umrah from al-Ji’ranah by putting on their ihram (Hajj garb) but leaving their right shoulders uncovered, bringing their ihram up from under their right armpits while covering the left shoulder. (Reported by Ahmad and Abu Daw’ud) The majority of scholars holds a similar view and claims that doing so is helpful in ramal (jogging) while making a tawaf. Malik is of the opinion, however, that doing so is not commended. for it is not a known (practice), nor did he see anyone doing so. There is consensus that it is undesirable in the tawaf prayer (salatul tawaf).