I' m going to design and market the FART MUFFLER.. I'm sure some folks will buy one!

They already do ,
it's called "ScentLok" ...

I can't describe how much I hate loud coughing when I'm hunting. There are times when I would pay 100.00 not to have it happen. I guess it may be a gimmick but if it makes you feel better while in the woods, then I say..."Go for it"....

i have the same problem i smoke a pack and a half a day and dont smoke when i hunt. Not more than 10 minutes after i get into my stand i have to cough, i carry a bottle of water with me and when i feel a cough coming a drink a little water it works for a litlle while then i do the same, it holds back on a lot of my coughing but eventually i still cough into my sleeve. Time to quit smoking i gues its just not that simple though.

If I carried any more gear into the woods I'd need a wagon for my backpack. LMAO

I bought one of those cough silencers and I am not sure what to think of it. When I cough, I cough from the bottom of my feet all the way up sometimes bringing oisters up with it. (I know it's nasty) But, with all that pressure in the cough, air rushes out of the corners of my mouth when the lips break their seal making a hissing sound.

Most times I just cover my mouth with the inside of my elbow.

I had the same problem ,
then I found that making a ring of your thumb and forefinger and pressing it around your lips as you cough into the muffler improves the seal . You also have to be careful to replace the cotton balls with just the right amount and placement for the thing to work at it's best . More cotton is not a plus and reduces it's ability to muffle the sound . It has to have some airflow to work right .