From Longman Dictionary of Contemporary Englishrub something ↔ in phrasal verb informalto remind someone about something they want to forget, especially because they are embarrassed about it Was he trying to rub in the fact that he didn’t think much of me? I know I should have been more careful, but there’s no need to keep rubbing it in. → rub→ See Verb table
Examples from the Corpus
rub in• Ay, there's the rub.• Always keep hand cream available in kitchen and bathroom and rub it in frequently.• Tall passengers often find their knees rubbing the seat in front of them.• He rubbed one in his hands to thaw it for me and barked at Nina, the black-haired girl.• Once he rubbed his shoulder in rather an obvious way.• He rubs the knife in the sand, rinses it in the saltwater, and hands it back to me.• He just goes around there to rub dirt in their wounds.• Just to rub it in, they hung the remains of the omni-gauge - a radio-navigation instrument - in the operations tent.rubbing it in• And it was like rubbing it in when I saw my patient. 