Always gay

Fred thought he had a great idea. His friend, Thomas, was gay and admitted he was sexually aroused by him. But too bad, Fred was hetero.
But when he found a spell to change the gender of someone, Fred thought it could be a great experience. Thomas was reluctant but finally agreed as the spell was temporary.

Fred recited the spell and, at first, it seems it worked well. Thomas, as a woman, was sexy like hell.
What they didn't imagine : Thomas had his/her gender alterated... but also his/her sexual preference. "Girl Thomas" was now lesbian.

"Yes, Fred, I'm SURE of it ! I'm not attracted to you anymore ! Not at all !"