The act of uttering what is considered to be the untimate insult to a guy, "you play ball like a girl!"
As quoted in the movie The Sandlot:
"Phillips: You bob for apples in the toilet! And you like it!
Ham Porter: You play ball like a giiirrrrrrrrl!entire group stands in shocked silence
Phillips: What did you say?
Ham Porter: You heard me.
Phillips: Tomorrow. Noon, at our field. Be there, buffalo-butt breath"
You have been Sandlotted!