So when my fellow student was talking about how he easily tires when he practises with another student (who is new and uses a lot of brute force), it is a revelation that he is still not able to relax when faced with force. He is still resisting.
Being relaxed doesn't mean giving space to your opponent. In fact, by being relaxed, all the more your opponent won't be able to come in. But it is human nature to push back when pushed. That is instinct. We train because we want to change that. We need to train long and hard to change that instinctive reaction.
And so I continue to walk this path.