She's shacking up with her boyfriend.

她和她的男朋友同居。

youdao

The man has been shacking up with the pretty girl for months.

这男子与那漂亮的姑娘同居几个月了。

youdao

She was found shacking up with three of the guys by her father.

她被她父亲发现跟三个男孩过夜了。

youdao

In New York, more than 250 families are still living in hotel rooms across New York paid for by the Federal Emergency Management Agency, while others are still shacking up with relatives or living in temporary rentals.

NPR: 6 Months After Sandy, Thousands Homeless In NY, NJ

Maybe if we could make it a hundred bucks instead of five it would be worth it along with an excise on shacking up to fund a program for non-marital domestic violence, which brings me to the lawyerly stuff in the decision.

FORBES: Taxing Marriage To Fund Domestic Violence Grants - Sense Or Nonsense ?