is it gay just to want to suck it?

No.

It's normal, healthy and beautiful for straight men to give oral pleasure to other men.

The human penis, when erect, is a thing of wondrous beauty -- it is God's most perfect creation.

And it is natural for all men to want to worship it with their mouths.  

Not necessarily. You can naturally be curious without being attracted to the same sex. Try it and if you like it, so what. 

Not automatically.  Being gay means being attracted to the same sex romantically and physically while feeling no such attraction for the opposite sex.  Desire to engage in some particular sex act does not define a person's sexual orientation.

Gay  sex is gay - by definition.

not if you are female............

It's called an oral fixation, an infantile sucking instinct. Common. Like smoking. Especially cigars. Only healthier. And better for the "cigar."

Ae we do not know the antecedent of 'it' we cannot possibly answer your question.

Probably. I have often wondered, about the fellow sucking mine. He's usually doing a  good job, but he says his jaw hurts from opening his mouth so wide, and he says if I move too much it makes him gag, he often says that there is too much to swallow without choking. I just wonder what is so pleasurable for you suckers about sucking it.

No. But it helps a lot.

Yes Mr Jaggoff, that's true.