Is it ok?
Define ok, because this would be a subjective answer that would vary by the person and the society or community in which one lives in.
It is an "unusual behavior" only in that one can assume that the ratio of people masturbating alone vs then with their friends is rather high. But this is a common occurrence nonetheless, many guys do masturbate together.
Is this a homosexual act? Again, this answer varies, some guys are less comfortable with themselves then others, and other guys don't mind showing off their johnson in public.
Agreed with marvel though, does it really matter so long as it doesn't harm others and deter yourself from a normal functioning life?