where the gay guy unbuckles his pants and the "Straight" guy jumps RIGHT on his dick and starts sucking away, like a starving person on a kfc dinner.
At least show some resistance and make it more believable.

gay guy: so do you like men?

"straight" guy: Naww man. Im straight. I like women only

gay guy: We'll see about that >>unzips and takes it out<<
how do you like this?

"straight" guy: FUCKING HOT!!! >>grabs it and starts sucking like no tomorrow<<

20 minutes later, the "straight" guys ass is stretched open like the holland tunnel, no difficulties getting fucked, he probably couldnt feel it.

"straight" guy: Well looks like im gay now

gay guy: yup. see ya around



-end scene-