If big ones are required, you need close contact and/or sneezing/coughing. If smaller droplets are sufficient, other vigorous oral activities like singing or excited close-quarters talking could spread the virus more effectively (choirs and professional conferences were important superspreader events in the early pandemic). Or maybe even just being together for long periods of time in unfavorable ventilation conditions.

In my recollection, epidemiological case studies have suggested that being together in unfavorable ventilation was the biggest risk factor overall. There were papers that looked at people's status, contacts over time, the rooms they were together in, and the ventilation conditions, all in a very detailed way and basically inferred the exact course of transmission between specific individuals.