Wiktionary
vb. (context informal English) To gain participation in an activity, especially an attractive one.
Usage examples of "get in on".
Yet when you get in on the inside of almost any standard- brand religion, you wonder what on earth the hush was about.
Investors are already lining up back on Earth to get in on a share of Lydia.
Very quickly all the thugs in the city couldn't wait to join the Nazi party and get in on the fun.
Human rights groups are going to get in on it, and in five short minutes, we'll have the newly formed Clone Rights organizations.
But if you thought that you should be able to get in on account of your name, or your clothes or maybe your bankbook, well, Hattie kept a straight razor in her apron pocket and her nephew, Junior Fornay, sat right behind the door.
Others tried to get in on it and proposed they form an excursion of death seekers and just go as far as Nassau for the preliminaries.