Soda water machines were very popular in the Soviet Union for decades. You could have plain soda water for one kopek or soda water with a choice of two syrups for three kopeks. Because those machines were ubiquitous and cheaply priced, young and old were lining up to have an ice cold carbonated drink on a hot summer day.
Now look at the black circle. A red pioneer is about to drink from a faceted glass that was symbolically rinsed with cold water before the use, with everyone drinking from the same glass.
Citizens of USSR did not worry about germs or infections left on the glass from all those complete strangers who touched and licked the glass before them. The glass wasn’t washed with soapy water or bleached.
Strangely, no one had ever heard of people getting infected through sharing a glass with thousands of strangers.
Today, many Russian doctors are sure that there were many cases of infection, but it was not customary to talk about it. At least dysentery was definitely transmitted this way, but all the data about such cases stayed within the walls of medical institutions and ministries.
Ordinary Soviet citizens did not know the statistics and continued to enjoy a carbonated drink from a shared glass.