Start by getting one piece of paper and folding one corner to the bottom so it will look kinda like a triangle. Next you are going to cut the strip so now it should look like a big triangle. Then you are going to fold one corner to the middle and fold the other corner on top of that folded piece, so both corner are in the middle now. Lastly you should only have the top part of the triangle that is not folded down, you are going to fold the one on the back side backward and the one on the front side fold that one forward but tuck it in the piece that was folded over the bottom one. and it will look like a flat folded piece of paper, so you are going to pull it open. and then you you have your own non leak-able cup.
I hoped you enjoyed this! I know that I did. I made these all last night, cause they were so addicting😄.