少年收起你的笑骚年收起你的电
[shăo nián shōu qĭ nĭ de xiào sāo nián shōu qĭ nĭ de diàn]
It's a play on words, urging teenagers ('shao nian') and naughty/flirty youth ('sao nian') to be more serious, literally saying, 'restrain your laughter and put away your charm/sex appeal.'