Well if this has been done already just call me slow or late to the game. Does anyone ever have sticky pockets? No not what your thinking, your juice leaking, oh well you know what I mean. Anyway I took a bottle for the grand and cut the top off and made a cover too keep the juice from leaking out of the air hole. My work is very physical so it gets turned every which way in my pocket during the day. After cutting the top off the bottle will need to be heated some to shrink it for a tight fit. I used a shrink wrap torch, heat gun or probably even a hair dryer would work. Then on the end of it you need to put a small hole about the size of the atty's air hole. This will help equalize the pressure taking it on and off, without it you'll have a mess. Note: I have a short drip tip on the REO, the longer style drip tips may not work as the bottle wouldn't be long enough to cover.
