light one up

Him(cute accent): You are so sweet and innocent, but also naughty!
Me: Haha
-I give him a mischievous grin-
Him: What are you doing this weekend?
Me: Shopping for Christmas lights at Urban Outfitters with my lesbian friend!
Him: You two are going to light one up!
Me: Hahaha!
-he looks confused-
Me: .....do you know what "light one up" means?
Him:......no
-I put two fingers to my lips and pretend to inhale-
Him: Ohhhhh!....are you sure?
Me:......no haha