What kind of STRAIGHTS do that? I've never heard a straight dude call someone else a daddy.
Don't be so close minded. You should get out more. Its really not that uncommon really. Guys talk shyt to each other (jokingly) like this all the time.
Ch some straight dudes dry hump, tea bag and horseplay with each other, what makes you think they don't play around like that with words in a playful way either?
But don't ask them, they'll deny they do this of course.