Got a bottle of Smirnoff, no shit glasses… how would you pace yourself?

I’ve tried vodka once out of a plastic bottle, no pacing, just like 2, 3/4 mouthfuls got me decently tipsy for about 30 minutes. So, I want to be able to do this semi-properly without buying shot glasses or anything like that because I’m bringing some to a hangout, but I don’t wanna go overboard. What should I do?