Japanese idols

A group of Japanese Idols decided to go back to someone's house after a long night of drinking.
After some discussion, they decided to go back to Yui's apartment. (Japanese people call television personalities "idols")

When they got back to Yui's apartment, they had a couple drinks. Soon, they realize the stack of fan mail and gifts in the corner of the room.
"Hey! Let's look at the letters!" One of the girls said.

"I have so many of these. I forgot all about them!" Yui replied as she reached out to the letters.

The girls started to open the gifts and letters from the fans. Many consists of videos made by Yuis' fans.
They decided to watch some of the videos, just to get some laughs.
Some were normal, where a man might be talking about how he wanted to meet Yui. Some were funny.
One video was a little weird, where there is a old man dancing in a middle of a room in his underwear. All the girls laughed, except for Yui.

The other girls noticed something weird, so they stopped and turned to Yui to see what was wrong.
Yui looked up, and pointed to the T.V.

"This man is dancing in my room!"