Śivasaṃhitā 5.230

The klīm in the heart is the vibration of desire (kāma) sublimated into spiritual love. That the bīja of desire resides in the heart—rather than the svādhiṣṭhāna as expected—reflects the tantric doctrine that purified kāma is devotion’s (bhakti) energy: the same impulse that seeks in objects can be redirected toward the Absolute.

Kāma-bīja = mantric seed of desire/love (kāma = desire, also the god of love), bandhūka = tree with intensely red flowers (Pentapetes phoenicea), kusuma = flower, prabhā = radiance. The strīm (or hrīm) between the eyebrows is Śakti’s māyā-bīja, brilliant as «tens of millions of moons»—an image opposite to suns: not intense direct light but soft, reflective luminosity.

The heart-forehead contrast in the bījas’ distribution is geographically significant: the heart is the center of feeling and kāma/bhakti, the Ajñā between eyebrows is the center of knowledge and śakti-discernment. Practicing the three bījas (aim-klīm-strīm) simultaneously activates the speech root, heart feeling and third eye vision: the three levels of human consciousness.