let someone stew in their own juice

let (one) stew in (one's) own juice(s)

To leave someone alone with their emotions, usually unpleasant ones like guilt, anger, or anxiety, without offering them comfort or closure on the matter. Kevin was in such a foul mood at dinner that I left early and just let him stew in his own juice. After the kids broke the window, I let them stew in their own juices for a while before laying into them about it. I can tell that the boss is upset with how my report turned out, but I think he's just letting me stew in my own juices about it before he brings it up.
See also: let, own, stew

let someone stew in their own juice

or

let someone stew

If you let someone stew in their own juice or let them stew, you deliberately leave them to worry about something they have done and do nothing to comfort or help them. The coach refused to put an arm round the 23-year-old afterwards — choosing, instead, to let Taylor stew in his own juice. Leave her alone — let her stew. Give her time to reflect on how stupid she's been. Note: You can also say that you leave someone to stew. I thought I'd leave him to stew for a while.
See also: juice, let, own, someone, stew