The messed up thing is that we stammer because we are trying not to stammer. I'm an aspiring SLP, currently a SLPA, who stutters and I would recommend keeping your muscles as relaxed as possible, because speaking 'is supposed to be' easy. I used to practice with DAF but I've resorting to just keeping an awarenesses of my mouth and throat while speaking, and also hearing what I'm about to say in my head. Sounds crazy but it works for me, good luck!