White yellowish smelly stuff stuck in the throat?

I am unsure what brought you to the conclusion about this type of condition but I never heard of a "sexually transmitted disease that occurs in the back of the throat with white yellowish smelly stuff."  This sounds more like tonsil curds, or tonsil stones.  Also known as tonsilloliths,  they are caused from matter such as debris and dead cells that accumulate in the crevasses of the tonsils.  You don't get these from having an STD.  Many people get them but not all people do.  You can use some salt water to gargle with or mouthwash to encourage them to dislodge out of your tonsils.