Yumka is a Dakini practice of the three roots of Longchen Nyingthik, the terma cycle reveled by Omniscient Jigme Lingpa.
Yumka is practiced on Dakini Day (25th day of the Tibetan calendar) in Namdroling and many other Nyingma monasteries and centers around the world. The central meditation visualization of the practice is on the wisdom Dakini Yeshe Tsogyal, a consort of Guru Rinpoche and the Founding Mother of Tibetan Buddhism.
Her dharmakaya is primordial Buddha Samantabadhri, her sambhogakaya is Vajravarahi and her nirmanakaya is Tara. All female buddhas are manifestations of Wisdom Dakini Yeshe Tsogyal.
The sadhana (practice) is one of the most profound practices in Longchen Nyingthik tradition. Beginning from refuge, it is the ground in the Dzogchen teachings. Because of this, Jigme Lingpa himself, and other great lineage holders wrote commentaries and practice guides on Yumka.