Try your team lead. Don't expect long philosophical conversations, but if they do a code review, make sure to ask "why?". Not like, "why, you dumbass?" but "why did you make that decision, what are the pro's and con's?"
I used to send emails to my favorite professors just to say hi, or to ask questions, I'm sure they enjoyed the conversation as much as I did.
I can definitely agree with this. Even though I've only held a couple of individual training sessions, the worst ones are where nobody asks anything and people just leave. No feedback on whether this session was any good or did I just completely blew it.
I'll gladly hang around to address any questions. It shows that you're genuinely interested in the matter. Don't be afraid of coming across as a beginner either - asking questions is how you learn.
I used to send emails to my favorite professors just to say hi, or to ask questions, I'm sure they enjoyed the conversation as much as I did.