He's shacked up with some girl he met in Berlin.

他跟一个在柏林结识的女子同居了。

She shacked up with some groomsman or something?

她和某伴郎有一腿吗?。

S said that he had shacked up with several girls before getting married.

据说在结婚之前他和几个女孩子过过夜。

They shacked up for over a year until her parents found out and stopped sending her money.

他们已同居了一年多，直到她父母发现并停止给她寄钱为止。