Sam, in my opinion, any man can be a BULL to any particular woman. If she holds you as fucking preference over her spouse or regular BF, then you are her BULL.
This website preferences black males as "Bulls" and usually follows with a photo or two of the Bull's rather larger than average maleness. Of course many are fake, but some aren't.
But, once again, you CAN qualify as a Bull to any woman who preferences you over other males she is screwing.
View attachment 3542990