Hey guys. I've watched it again and I think I got it.

At the attraction part (bar heartful) Shuuta was playing as a thief, which is 'Goutou' in Japanese. on the credits were written ''Thief (who steals people's heart)''
At the member call, after Shuuta did the bakku tei, I think they were talking about how the crowd was excited by shuuta. Hidaka said 'koufun shimashita' (=they're excited/aroused). shuuta said 'goutou-san yoku ganbatta' (=mr. thief has worked hard) which I think refers to Shuuta's role.

I'm pretty sure of this, and now I'm kinda disappointed that they're not talking about Yukarin :(