大毘盧遮那成佛經疏 14.7

14.7

次左手舒掌，而屈地水二指入掌中，迴風指捻著火指之背，空指亦稍句屈，即是嬌末離礫底印也（礫底是器物印也，圖如之）。此是大自在之子名羯底迦，此嬌末離是其妃名也。

Next, extend the palm of the left hand, bend the two fingers earth and water into the palm, turn the wind finger to pinch the back of the fire finger, and slightly hook and bend the space finger; this is the Kaumārī Śakti mudrā (śakti is an implement mudrā; the drawings illustrate it). This is the son of Maheśvara named Kārttikeya, and this Kaumārī is his consort's name.