follow (one's) nose
1. To walk straight ahead (thus walking in the direction that one's nose is facing). A: "Should I turn here?" B: "No, follow your nose and keep walking in a straight line—you'll be at my house soon enough."
2. To follow a scent, in an attempt to find its source. I thought I smelled something baking, so I followed my nose down to the kitchen and found my mom icing a cake!
3. To take action based on one's instinct. I tend to follow my nose when I have a bad feeling about someone, and it's helped me to avoid a lot of drama.