I did this a couple of times in my friends basement. We bought beach balls last summer and we smoked in the basement with a glass bowl. We would hold in the hits a while and then blow the smoke into the beach ball. One beach ball takes a while to fill up and if each person has one beach ball for themselve, you can get like 2 sessions out of it. Then wait a while and then empty them outside. The smell sticks to the inside of the beach ball so no one know that the air coming out smells like weed. It worked pretty damn good.