sneak around 偷偷摸摸，鬼鬼祟祟

When I want to smoke, I have to sneak around because my boyfriend doesn’t like it.

我想抽烟的时候必须偷偷摸摸的，因为我男朋友不喜欢。

He is sneaking around behind your back.

他在你背后鬼鬼祟祟呢。