Kinda depends, but yeah, if it's a really good friend.
Certain friends i`d only jump in to stop them from taking a really bad L, others are like family and they're fighting all of us.
I remember one time in college my boy Mike was walking down Main St. hollering "fukk the police, all you are fakkits"
Some drunk white dude yells up "Oh yeah, fukk police?"
Mike "Yeah fukk them and fukk you too nikka" (He's a spanish dude always using the n-word, literally every 4 words, it's hilarious)
They come to meet up, my man Mike is just shytting on this guy verbally, so they get to the point to scrap, one of his boys says Ok, no one jump in though let them fight it out. I say "no doubt" and a second later punch the big white guy in the face and then Mike goes at him.
My ass ended up tossed "in da bushes" no joke, me Mike, the big white guy and his friend who all got arrested that night. Funny story all in all though.