With respect, the content of this thread is moronic.
First off, I know the dictionary changes definitions often these days and what we defined as a woman five years ago may now include 60 year old men who shave twice a day, but as far as I know, "Tranny" is still short for transvestite, which is a GUY, dressed as a woman.
Secondly, Thailand is generally acknowledged to be ground zero for men who can come close to passing as women. I will grant that some can make you look three, even four times and still be in doubt-especially if they're a few feet away from you. But of the literally hundreds that have hit on me over they years there, ZERO could leave you in doubt after a five minute conversation. Maybe technology will change this, but for now, it is...excuse the expression, a pipe dream.
The OP is mortified that he may have fucked a guy, but wasn't concerned or intelligent enough to find out at the time. Gimme a break.