Then comes the next question... when you come, do you take it in the face, or in your mouth?
Do you swallow?
Do you come back for more?
It may not make you Gay... in that it may not make you any more inclined to want a romance with another man...
But over time, it does make you a cocksucker.
You get used to the sensation of a cock in your mouth, your brain begins to conflate the pleasure of getting your cock sucked with the sensation of having a cock in your mouth.
The visual stimulus of seeing that thing coming at you, looking down the barrel, feeling it surge and jet warm cum into your mouth...
The tactile stimuli of the hardening shaft in your hand and the satin smooth glans on your tongue, the sweet drizzle of precum... the texture and the tickle of fresh semen sliding down the back of your throat.
Sucking yourself will condition you to the experience of orgasm being associated with all these sensual inputs... you will find yourself excitedly anticipating the cock on your lips, the taste of cum in your mouth, or the feeling of it splattering across your face.
It may never go any farther than that....
But, once you are conditioned to react lustfully to cock in your mouth, you will react lustfully to the very idea of cock in your mouth...
And, should the opportunity arise, ( especially should it arise without danger of consequences) should you find yourself with the option of sucking some other guy's cock in a situation where no one you don't want to know would find out...
Then you will probably be willing to suck another guy's cock... and then you will discover how much more fun it is to suck cock when you can really take the thing down your gullet... and NOT get a huge crick in your neck...
Even this, however, will not necessarily make you gay.
It is entirely possible to be a Straight man in terms of attraction... who nevertheless is an eager cocksucker.
In fact... I think that 50% of the male population harbor secret thoughts of sucking cock. ( and I do not mean the 10% that are gay )
And I am certain that most males have the capacity to be bisexual if women are not an option.