Meaning of “MenChika(メン地下)”

“MenChika(メン地下)” is an abstraction for “Men’s ChikaIdol(地下アイドル)”.
It means Male idols who are not signed with major agencies and mainly perform live shows.
*Basically, “ChikaIdol(地下アイドル)” refers to female idols

Some women become so obsessed with “MenChika(メン地下)” that they spend large amounts of money on them, which has become a social concern in some cases.

Example Conversation

A: Are you doing some “OshiKatsu(押し活)“?
B: Yes!! I’m into in “MenChika(メン地下)”.
A: Oh, are you okay? Don’t go into debt from spending too much, alright?
B: I won’t! The idol I support is totally wholesome!

A: 推し活とかしてる？
B: してるよー、メン地下にハマってる！
A: え、大丈夫？大金つぎ込んで、借金したりしないでね
B: しないよー、私が推してるのは健全なメン地下だから！