Most of the guys signing up are married or in long-term relationships with girls.
They'd hit girls or shemales - but not guys looking like guys.
Some like cock on the tgirls some are in it just for the ass.
Some like to top the tgirls - some like to get topped.
Most would class themselves as bi-sexual or straight with a twist.
It's a fetish more than a lifestyle - same as strap-on chicks fucking guys, they're in it for the kick or the sex but don't want to live like that all the time (well some might).
Try promoting these sites:
http://www.shemaleyum.com
http://www.shemales-from-hell.com
http://www.ladyboy-ladyboy.com
http://www.black-tgirls.com
http://www.brazilian-transsexuals.com
http://www.franks-tgirlworld.com
http://www.joey-silvera.com
seanchai