What would you write on a lighter to prevent someone from nicking it?

I live with a stoner and I like candles, so unfortunately I can't ever fucking light them.

I'm pretty artsy and have everything to customise a lighter in any way possible. I was thinking making it horribly uncomfortable to hold (he gips even looking at seude) but writing would be a easier option, something that he'd be absolutely ashamed to get out in public. Any ideas?