Indeed it's interesting ! Even something as common as taking a jacuzzi can help me being fluent next day. It's a matter of stress inside your body. Hmm pretty sure the event(s) was all the way back when I was a little kid. Must've been traumatized by something I don't remember and it got carried with me since then. I'll definitely go check this out though. Something else that I wanted to try for a long time was to go in Northern China to train and meditate with Monks, could really help :)