Vijnana Bhairava Tantra
एवमेव निमील्यादौ नेत्रे कृष्णाभमाग्रतः । प्रसार्य भैरवं रूपं भावयम्स्तन्मयो भवेत् ॥ ८८ ॥
Similarly, while closing the eyes, one should contemplate on the profound darkness spreading in front as the form of bhairava. Thus he becomes one with that.
english translation