During energy interactions creatures can ask for energy.

It is done by coming close to the creature, pointing at it and selecting "ask for energy" in energy interaction menu.

Creatures have a choice of giving energy or refusing to give it.

Creatures also can ask energy from other creatures with whom they're united. This is done by pointing on oneself and selecting "Ask energy". The other creatures would receive the call and if they'll selects to give energy they'd immediately start walking/flying on their maximum speed to help his friend.