Set Harth wrote:
It's not just the appearance of the word...
1) Batman is pulling his boner in public.
2) The Joker is trying to force Batman into a boner.
Yes, and considering the context of the time and use of the word "boner" is being used as an "error" or "mistake" it's not very funny, is it? All people who find that funny are doing is seeing "boner" thinking "erection" and then giggling like a middle-school kid.
I see the word, know the context and don't find it humorous because, well, I know what it's talking about.