There is an official way to run a relay on OS X, but warning: It can get messy!
First, you will need to install Homebrew. Instruction at https://brew.sh/, or run the following command in Terminal:
/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
Once that command finishes, run the following command in terminal
brew install tor
Once that finishes, Terminal might ask you to patch it or something by running a certain command, which I had to. Use the commands Terminal will give you to patch whatever it says to. Once that is done, on the OS X menu bar click Go -> Go To Folder and go to /usr/local/etc/tor/. There will be a file called "torrc.sample" Open this file. At the bottom of the page, type in this information:
ExitPolicy reject *:*
Keep in mind, the port number you choose next to ORPort needs to be configured for port forwarding on your router and firewalls if you have any. Also the email address you put will be publicly listed on your relay information in the tor network, however I'd recommend using one that works as tor will send an email to this address if the relay is not working correctly, etc.
Unfortunately the things you have to run and patch in terminal can get a little messy. Let me know how it goes buddy.