A Japanese tease term mo-fo (MOmo FOreigners) originated in early 2013, to describe groups of foreigners hanging out in Tokyo's fashion districts (Shibuya, Harajuku), typically rude, nagging others passing by. Generally don't speak any Japanese.
Momo, in Japanese, means
peach. Although the origin is uknown, it seems momo part originated from the famous Shibuya's
annoying mascot (Momo-ko), that was
popular back in the 90s.