大毘盧遮那成佛經疏 13.214

13.214

次舒右手而托右頰，稍側頭就手，少許相去，即是淨居天印（此是思惟手也，一名自在天）。

Next, extend the right hand and support the right cheek, tilting the head slightly toward the hand, leaving a small distance—this is the Śuddhāvāsa Deva mudrā (this is the contemplation hand; another name is Maheśvara).