Dear,

i cannot make out where are you located, but some leather stores, especially those that deal with fetish clothing might be able to help you. Also – just a suggestion, look on line for leather gags, leather ball gag, leather penis gag etc. while i personally love leather, i don’t like the taste of it in my mouth. Obviously you do not have much choice (being allergic and all) but apart for store bought, home made ones maybe of the tick silky rope, knotted, used together with some cloth, or the metal ring and leather gag one on top of some cloth in your mouth (which can than, conveniently be pulled out to free mouth for some better stuffing...) will do nicely, i think