You follow a friend or acquaintance on a social networking site (Instagram/Twitter) in exchange for them to follow you. You don't really know them, it's used to boost followers but with people you kinda know. It's called a "mutual follow" because once someone unfollows, the other follows suite.
"Did that nigga really unfollow me? thought we had a mutual follow, I aint interested in yo shit either bruh"
by Derack January 10, 2015