The phrase is often used literally to describe someone physically blocking light, making it hard for others to see. Can you shift to the left? You're in my light, and I can't read this book.
Pro Tip 2/3
Polite Requests
Use the phrase to politely ask someone to move without sounding rude; it's a gentle way of pointing out the issue. Excuse me, you seem to be in my light, could you please move aside?
Pro Tip 3/3
Apologizing
When you realize you're blocking someone's light, use this phrase to apologize and move out of the way. Oh, I'm sorry for being in your light—let me move.