To add a Sour Punch Straw to a can of beer. This makes the beer foam and adds a sweet taste.
We don't got lotsa drink money so we jus' went down to the corner store and made us some Redneck Tequilas
In the context of Martial Arts, to practice in a way that more resembles a Role Playing Game than an actual fight, and/or to overdo it with terms from other languages, elaborate costumes, etc.
One may LARP as a Samurai or Ninja (Aikido, Budo Taijutsu/Ninpo), Buddhist monk (Shaolin Kung Fu),special forces soldier (systema, various forms of "street self defense), even a member of another culture in your own country (52 hand blocks).
Did you see those idiots dressed as ninjas demonstrating how to beat a sword with horse stance? Total LARP.