Lee's face was full of serious enthusiasm until he realized it was Kakashi who had answered his knock, and then the young Genin's expression changed and he gave Kakashi The Look. The Look clearly stated 'I don't understand this and I'm not sure I like it, since I'm wondering if you didn't seduce Gai-sensei with some impure wile, but as you are now Gai-sensei's Dearest One, I will jump in front of a kunai for you'.

"The art of love will be my challenge. We are going to measure our prowess as men. I challenge you to a battle to determine which of us is the better lover!"

Kakashi lives in the darkness, which is more than he deserves, but for Naruto he'll step into the light.