do the dirties with someone—(sl.) have sex with a person:
- You just don’t understand that Sean and I are just friends. I don’t plan on doing the dirties with him.
do the dirty on someone —(coll.) do smth. bad and unfair to a person (also: do dirt to someone):
- The Germans have been “doing the dirty” on us by donning khaki and kilts to approach our trenches.