There are too many indirect expressions to write down so I will write some examples.
> () to 'share' the sheet
This is pretty old fashioned way to say English equivalent would be to get shacked
e.g. ―
> () to exchange pillows
This is also kinda old fashioned way but makes sense to most adults. A literary expression.
e.g.
> () to form a battery
This is a kinda slang but not so dirty. I often hear single middle aged women using this expression.
e.g. A < friends of my mother >
> () () to fight a battle with
I like this expression. Sounds formal at the same time humorous.
e.g.
> () aventure from French word 'l'aventure'
Young gal word I suppose. Often seen in world of popular song. Men rarely use this expression.
e.g.