Sesame seeds sprang from the limbs of the great Rishi Kashyapa. Hence in the matter of gifts, they have come to be considered as possessed of great efficacy.
महर्षेः कश्यपस्यैते गात्रेभ्यः प्रसृतास्तिलाः। ततो दिव्यं गता भावं प्रदानेषु तिलाः प्रभो॥