when your friend, pal, colleague, cheerleader, or someone of a close affinity is by your side (either figuratively or literally) to makes sure that you make it through the troublesome, difficult, or tedious time or predicament you are currently in.
craig: oh, arianna, are you ok?
arianna: i just can't get this cheer down. I don't think I'll be able to do the perfect cheer.
craig: You can do it! I know you can! I got your back.