When someone asks to "pick your brain", they typically want to learn from your experience and knowledge. But there are plenty of other ways to express this sentiment. You can say you'd like to "tap your expertise" or "draw from your wisdom", for example. Other options include asking for insight, guidance, or advice. If you're looking for a more informal approach, you can say you want to "pick your brain cells" or "run something by you". Whatever you choose, be sure to convey your appreciation for the other person's expertise and willingness to share it.