Idiom
pat someone on the back and give someone a pat on the back
Theme: PRAISE
to congratulate someone; to encourage someone.We patted Ann on the back for a good performance,When people do a good job, you should give them a pat on the back.
Idiom
pat someone on the backpat (someone) on the back
a pat on the back - if you give someone a pat on the back, you praise them for something good that they have done.Too many people are patting the players on the back and telling them how great they are.