When you offer to a guru, the buddhas come into the guru and receive the offerings, and this also pleases them. The Tibetan master Lopon Sangye Yeshe wrote that when you’re devoted, the buddhas enter the body of your spiritual teachers and receive your offerings, thereby purifying your negativities, allowing you to quickly become enlightened.
Gyumed Khensur Rinpoche Losang Jampa. The Easy Path. Wisdom Publications. Boston:2013