Why can't orphans suck dick?
Because they don't have a stepbro.
Alright, listen up, you clueless dingus. This "joke" is playing on the stereotype that stepbrothers are horny and want to do the nasty. The punchline is that orphans don't have stepbrothers, so they can't participate in this kind of activity. Get it? Probably not, since your brain is the size of a peanut.
Dwoodles
No.