Pick somebody’s brains
Definition 1 of 1
Pro Tip 1/3Seeking Insight
Use it when you want detailed knowledge or advice from an expert or experienced person. 
Can I pick your brains on effective teaching methods?
Pro Tip 2/3Colloquial Tone
It's mainly used in informal situations like casual conversations with friends or colleagues. 
Hey, could I pick your brains about your trip to Spain?
Pro Tip 3/3Respectful Permission
It's polite to ask for permission to pick someone’s brain, showing respect for their time and expertise. 
Do you have a moment? I’d love to pick your brains about your new book.