Heimlich Maneuver anyone?

Last night we went over to Grandma and Grandpa Erickson's house for dinner, we like to try and get up there a couple of times a month. We Erickson's enjoy our pig swill (aka: koolaid with fresh lemons), Aubree had decided she could be careful with a regular glass, instead of a sippy cup. When she took a drink it must have gone down the wrong tube, because she started to cough and cough. Once she was able to compose herself she thought it was funny and would randomly try to cough again which would just make us laugh. Grandpa Robert then took a drink and couldn't stop coughing, and then both uncles at the other end of table while eating bread were coughing. I couldn't stop laughing, who know coughs were contagious?