Help with xfinity commercial?

There is a recent xfinity commercial out and the guy is demanding all this stuff written on his hand with ink. He unknowingly wiped his forehead which caused ink to smear on his forehead. The girl says "you have something right here" and then he says "so I'd like to think". What is he referring to when he says that?

He is referring to her comment which he considers a compliment. He assumes she means he has a sharp brain. He has no clue that he just smeared the ink.