If you have a school-wide subscription you can invite other teacher's from your school to join, here's how!
Step 1: Log into Flocabulary, hover over your name, and click "My School".
Step 2: Type in the emails in the "Enter an email address" field. Press return to add as many as you'd like! Press "Send Invites" when you are done.
If you're a a subscription manager and want to invite teachers check out the instructions here.