大毘盧遮那成佛經疏 13.183

13.183

次摩麼鷄印。如前五股金剛，其二空指二地指皆入掌中，亦右壓左，即如前向內叉合掌無異，但火風指如金剛也（金剛母也）。

Next is the Māmakī mudrā. As with the previous five-pronged vajra, the two space fingers and two earth fingers all enter the palms, also with the right pressing the left; this is no different from the previous inward-interlocking clenched-fist añjali, except that the fire and wind fingers are like a vajra (she is the Mother of the Vajra).