Hi guys. My friend wants me to shoot photos of guests at his next houseparty (there's usually a couple of hundred people there, it goes wild) and I want to shoot photos like you see in nightclub pictures etc, you know the ones where you see the guy walking around the floor and taking photos of people? I currently have a d7200 with a 35mm f1.8, and I'm seeing from posts on the Internet most people reccomend getting an external flash to bounce lights off the walls and stuff. I can't afford a flash right now, I was just wondering if there's anything I can do without one in this situation, would having my in built one and setting it on rear curtain sync give me the result I want? Also considering the low light and whatnot, to generalise what settings would you guys reccomend for such shots? Obviously it won't be exact, but for a base of a starting point it would be good to know

thanks in advance!