Maa Kaal Bhairavi 

II Om Tripurayai Vidmahe Mahabhairavyai Dhimahi Tanno Devi Prachodayat॥

O mother Maha Bhairavi , help us transcend all earthly desires for union with the cosmic energy and with your divnity may our  hearts that are filled with darkness be illuminated with knowldge, spirituality and bhakti. Keep the darkness of ignorance far from us. 
She is the supreme cosmic energy that governs the three planes. -physical, astral, celestial (bhu, bhuvah, swarg. Maa Bhairavi in her Chandi form is the slayer of the asuras Chanda and Munda. She is the ferocious one who kills all barriers that block the path to reach supreme infinite cosmic enrgy l i.e. barriers of the mind. Some of these barriers or blocks include- "sickness, doubt, delusion, incompetence, sloth, non abstention, erroneous conceptions, non attainment of any yogic state and these result in fear."
She is the Kriya Shakti, the doer who clears the path for cosmic union of the ssoul with the suprasoul, consciouss with the supra conscious, energy with the infinite cosmic energy.  She blesses the sadhaka to overcome lust, envy, angeravarice, spirtual ignorance and pride and pushes the energy of the kunadalini upwards.

II Om Hum Chinnamastaye namoh namah II 

Glory and obesience  to the Goddess who severed her own head as self sacrifice and for awakening the kunadalini and spiritual energy.

Also kown as prachanda Chandika is the ferocious form of Shakti and is like a red hibiscuss. She is the one who blesses a sadjak/ sadhika to gain complete control over ones physical and sexual senses so that union with the infinite cosmic energy is possible. She dances the tandava and is like lightnining. Once aroused she gushes up the kundalini opening up all chakras while at the same time detaching from physical and sexual desires. The head which she severes her self ndicates the separation of the wondering mind from the objective of union with cosmic infinite energy. The three springs of blood gushing out from the severed part f her neck is drunk by her herself (Sushumna "Sushumna is a Sanskrit word meaning "very gracious" or "kind" and is also the name for the central nadi in the body. Anatomically, the sushumna runs down the central axis of the body, through the spinal cord. The sushumna nadi is the most important nadi of the astral (emotional) body." ), and by her Dakini and Varini (ida-lunar energy and pingala-solar energy). 
She is seated on the body of kamadeva and Rati indicating that lust has no control over her and she is beyond physical and sexual desires. her only objective is union with the supreme energy. 
Fiercer than even maa kali she is Prachanda Chandika
What we learn from her is cosmic conciousness is greater than anythig else. We need to open our channels to connect with cosmic energy and for that we need complete control of our senses.