Over the years I've noticed that, especially very early in their careers, well schooled boxers have trouble with "wild" fighters, at least for a round or two. This is because they don't do anything right because they don't (or do they?) know what they are doing. In boxing you get to expect the other guy to do certain things because that's what you, and everybody else, does.
I also tend to be pretty patient of just about any type of boxing, having engaged, at some point, in every one of them, I think. So, when you and your lacrosse pals put ont he helmets and swap blows, try this with the wild swingers.
Left shoulder and hip forward, chin down hands up, and step in REAL close to him. Put your left shoulder and forehead into his chest and then punch him in the body. This and his wild swings will soon cause him to become 'winded', at which point he will either quit or stop swinging, at which point you can get some room and start landing your own punches.
This is not to endorse or recommend any type of irresponsible beating the hell out of one another, just something that has worked well for me in similar bouts of mayhem among mates. Good Luck!