I know I don’t talk much about myself here on the blog, but I am indeed a bearded man [my name’s Adam]. I personally don’t trim my mustache and I understand the frustration of eating with a larger mustache. especially when it gets in your mouth and in the way when of eating. the solution I’ve come up with, is training my mustache to spread off to the sides. It works pretty well, but i do constantly have napkins with me to help keep things clean. You can try waxing your ‘stache for more control.
or you can do as my friend Lucas does [he’s got a massive mustache that easily covers his entire mouth] - lift up the mustache with one hand and use other to eat as you normally do.