Ask HN: Where to go for short term expertise?

generally while learning something new i catch hold of my colleagues who have prior experience with what i am trying to learn. I ask lot of stupid questions initially but get upto speed relatively quickly. Unfortunately this technique does not work if i don't find the expert i get blocked by my stupid questions and endless search for answers in stackoverflow/irc/slack without making much progress. Any idea/suggestions/pointers on where to go to find expertise?

PS: I don't mind paying for the expertise either.