Smingus Dyngus (or just Dyngus) is a traditional ritual celebrated on the first Monday after Easter in Poland. On this day boys wander around with buckets of water and water pistols in order throw or sprinkle water on any girls they can find. Traditionally they would only throw water at girls they were attracted to but in recent years any female will do, no matter how old or unattractive. Men are also sometimes targeted! This water-based Polish custom probably has its roots in pagan traditions where the pouring of water is associated with cleansing and purification.
This webpage is about the Smingus Dyngus / Wet Monday / Lany Poniedzialek Easter tradition.
Other Easter related content on the Polish Poland website: Easter in Poland.