save/spare somebody's blushes
save (one's) blushes
To prevent someone from feeling embarrassed or awkward. Due to your family's great service to the crown, we will save your blushes and not create a public scandal around this debacle. I tried saving her blushes when she asked me to prom by saying I had no intention of going with anyone.
save/spare somebody’s ˈblushes(informal) not do something which will make somebody feel embarrassed: Don’t tell everybody about his excellent exam results. Spare his blushes.
A blush is the red colour that spreads over your face when you are embarrassed or ashamed.