Adj. Used to describe questions asked to one seeking entrance to a fringe group/political cult. A dog-whistley question lets true believers know it's time to talk about the hard core stuff. "Samantha" on WEB OF MAKE BELIEVE (Episode 3, "I'm Not a Nazi") used this phrase to describe the way white supremacist group, Identity Europe, delicately asked her about "the Jewish Question."
These skinheads were asking me these dog-whistley questions about other races and then I realized they wanted to recruit me.