嗯哼嗯哼蹦擦擦欧耶欧耶欧麦嘎
[ng4 hēng ng4 hēng bèng cā cā ōu yē ōu yē ōu mài gā]
It's an expression that combines random interjections and imitations of dance or party sounds. '嗯哼' ('hmm') is like saying 'um-hum' casually, while the other parts imply joyful noises people might make when dancing or having a good time.