if it is falling off the roof of your mouth then you prblyhave it to far foward you should try pushing it abck a little bit thats what i found. and as fo triming it. i wouldnt do it. you get the best sound when no air passes around it. no body can really tell you how to use it because its hard to explain over the internet hah but just listen to turkeys in the field or listen to hunters on movies.

hope it helps

good luck this season.

tc