get it on—(U.S. sl.)
1. begin smth. with energy and enthusiasm:
- You want to go for pizza? Let’s get it on!
2. have sex:
- Just as they were about to get it on they heard a giggle from the corner of the dormitory.
put it on—(UK coll.) assume a false appearance; feign smth.:
- Billie is just putting it on, and sounds like Americans in movies where they pretend to be English.