Wiktionary
get it over with
vb. (context idiomatic English) To do or finish, especially said of something unpleasant.
Usage examples of "get it over with".
Well, if she was going to lose her mind again, it would be nice to get it over with.
I guess she thought it would be better for Jessi to get it over with, so she could stop feeling so nervous.
Some people, all this buildup, and then it's, Hey, let's get it over with.
It wouldn't do any good to argue with the officer, so he'd go down as quickly as possible and get it over with.
Few of them were aimed in his direction anyway, and if his luck was that bad he'd better get it over with.