I've noticed this. It's not a cure; the effect is less over time (same with other depressant drugs), so please don't become an alcoholic. Why it works? Alcohol makes it easier to be out of control. The way I think about it, there's an "automatic" process for speaking and a "manual control" process for mouth movements. To protect against rejection/mistakes, stuttering tries to "error-check" the "automatic" process using the "manual control" process, which doesn't work. Speech therapy teaches transitioning from the "manual control" process (exhale, slow voiced speech) to the "automatic" process. This helps a lot but the "manual control" process is still overused. My "trick" is to accept that I have no control over what I will say in the next 5 seconds. I accept that my subconscious mind has total control over when I start speaking and exactly what I say. I can make saying some things more likely (e.g. by practicing a speech, or thinking about my goals) but ultimately it's an automatic process and I only have to stand there and let my subconscious mind do its thing.