(tib.: tong len) Literally it means giving (tib. tong) and receiving (tib. len), so in English it is often called taking-and-giving meditation. This meditation is one of the methods to develop Bodhicitta. It involves your taking other beings suffering and its causes onto yourself when inhaling, destroying your ego, and giving your body, happiness, merit and all the good to other sentient beings when exhaling.
It is similar to metta practice.