Mr. Nice Guy said:
I disagree. I would say years of homophobic socialization have left a lot of men thinking that if you aren't horrendously disgusted by the site of another mans dick that you must be gay. In reality, the site of another man to a straight man should elicit NO reaction. We have been socialized to associate certain areas as private and therefore deserving of some reaction when seen. If anything, to a truly straight man, seeing any part of another man would have the same reaction as if seeing another mans arm, it doesn't mean anything. To a straight man wathcing a porn with a guy fucking a girl, the dick is there because it has to be, not because the man wants it to be.
Having said that. If you are comfortable touching another mans dick in any way, there is no question that you may be playing both sides of the field or a full gay. Straight is indifferent not accepting.