'X Factor': Nick Jonas finds Jillian Jensen 'sexy' and more guest-mentoring bon mots

For the judges' homes visits on "The X Factor," when each judge whittled their six acts down to four, each judge also welcomed a guest mentor to help out. At the house for the Young Adult group (18-24 year-olds), Demi Lovato welcomed fellow pop sensation Nick Jonas.

Some of his highlights include:

About Willie Jonas: "Sometimes he's R&B and sometimes he's country. I do think there's a place for him, but he's gotta define that."

About Jillian Jensen: "Maybe it's out of line, but she's kinda sexy. There's something sexy about her. It's the voice tied with the passion in it."

About Cece Frey: "She took direction extremely well."

What did you think of the youngest Jonas brother? Did he do a good job? Or just kind of sit there?