The five of us (three guys and two girls including his future wife) who always got together to study at the library were there as usual one night about 9 PM. He kicked me under the table and made a non verbal gesture to me that he was about to let out a silent one. I laughed at this possibility which in turn made him laugh just as he was about to do so. That turned his slow silent effort until a VERY loud one. It was so utterly loud that everyone within site heard it including other students who we saw every night but didn't know (we had our routine places to study). One female student was so startled that she jumped up and hit her head on the study carol. The five of began laughing uncontrollably (the two girls got over it and were more embarrassed than anything) and we could not stop laughing. We had to leave the library for the evening and worse, we had to find another section in the library to study since the girls had no intention of returning to the scene of the crime. I still laugh when I think about it because the whole episode was unintentional.