No, that's not necessary. You can even nurse while fast asleep if the baby has a good latch.

And yes, there are babies that perform self-service. It's a good way not to have a sleep deprived mother.

I should have known this, but I'm glad I know now before assuming in real life. Thanks!

Thats usually not needed. Towards the end of the breastfeeding session when the baby has drained much of the milk, mothers will often massage the breast to push more milk towards the end. That can make milk squirt out, but it isn't the purpose. Really full breasts can definitely leak milk without any suckling, but most of the milk comes out as a result of the baby suckling.

This reminded me of Miike's "Visitor Q".