This is the way I do it. Just try to picture it in your head as I go along. With the half moon hole on top and the call in your left hand, place one corner of the reed under your left thumb to secure it. Make sure when you lay the latex across the opening it lays in a straight line across the upper rim of the lower lip stop. From a relaxed position, pull it approximately 1/4" with your right hand. This may vary a little more or less depending on the type and thickness of the material. Lay it down the other side and catch it with your middle finger of your left hand. Now you have it stretched straight across the call between your thumb and middle finger with the bell end of the tube resting in the center of your palm. You have a good straight line across the call with your latex. Now with your right hand again, grab the latex on the upper/center part of the reed and stretch it upwards to give your latex a half moon opening. The opening doesnt have to be really large. Around 1/8" of an inch of gap in the center should be plenty of pull. Now press and hold the center of the latex down to hold that profile with your pointing finger in the center. Now you have your thumb and first two fingers holding down the three anchor points of the reed while holding the call in your left hand.
Now is the time to test the sound of your call before you put the O-ring on. If you like the sound, great. If your not happy with it, re-adjust it to your liking. That's the good thing about a tube call. You make it sound the way you want it to, not the call maker.
When you find the sound you like, put on the O-ring. Start at the top/center of the call and lay the O-ring into the groove and then gently go down evenly along the sides from there. Once you have it seated past the area that the reed is located, you can pull the O-ring down around the bottom half of the call. Try not to make the O-ring twist and roll into place. The method of putting the O-ring on is kind of important because a lot of times it can cause the latex to get a little increased tension which will raise the pitch of the call after you tested it. If the groove cut for the O-ring to sit in is rather deep then more than likely it will stretch the latex a little bit while it is being seated so you may have to adjust for that while tuning.
Play with it a few times and you will get the hang of it pretty quick. Test it and get the O-ring into position and see how it sounds. If it sounds good, do it again and try to see if you can get it a little quicker next time. Sometimes you may have to fool with it in the field and you dont want to sit there for 30 minutes fooling with a call instead of using the call.
Hope I have not confused you any with my ramblings.
Travis
