A person who is Dick Casual is tends to be quite casual around dick.
In terms of men, being Dick Casual doesn't necessarily make you homosexual. It only means you are casual around dick.
In terms of ladies, being dick casual might be looked down upon within your gender group. Women may try to be a bit more Dick Formal.
Markarita: Yo. You gay? You a homo?
Mauricio: Na, just dick casual.
Popsee: Hey buddy I notice that you don't freak out anymore when penises pop up left and right on Chatroulette!
Seedsee: Yeah I know. I am so used to them now...I have become quite dick casual.
Jorge: Bro. Tonight's gonna be a total sausage fest. No girls at all! So many guys! AH!
Mercutio: Its all good man. I don't mind and I am perfectly secure with my straight sexuality too...
Jorge: wow...you're so dick casual.