in bed with

in bed with somebody

1. secretly helping someone and receiving help from them in return The senator isn't the only person in Washington who's in bed with military equipment manufacturers.
Usage notes: usually used negatively about a political relationship, as in the example
2. having sex with someone She found her husband in bed with another woman.
See also: bed
References in classic literature ?
He carried it that length that he protested to me, that if he was naked in bed with me, he would as sacredly preserve my virtue as he would defend it if I was assaulted by a ravisher.
But I don't fancy having a man smoking in bed with me.
cries Maclachlan; "do not I know Mrs Fitzpatrick very well, and don't I see that the lady, whom the gentleman who stands here in his shirt is lying in bed with, is none of her?