What did George do once that made him stop playing jokes on Lennie?Of Mice and Men by John Steinbeck

[Questions had to be eliminated since students are only
allowed one question at a time.]

In Chapter 3 of
Steinbeck's novella, Of Mice and Men, as they play cards together,
George responds to Slim's "calm invitation to confidence" after Slim asks him why he and
Lennie travel together.  George explains that they are from the same town, and when
Lennie's Aunt Clara died, Lennie just "came along" with
George.

As an afterthought, George explains  that he used
to have fun with Lennie by playing practical jokes on Lennie.  But, because Lennie was
so simple in his thinking, he never understood that he was being teased.  Instead, he
would dumbly obey George.  In fact, Lennie was so devoted to George that George could
tell him to do something harmful, and Lennie would do it.  One day, George told Lennie,
who did not know how to swim, to jump into the water.  When he nearly drowned, then
thanked George for getting him safely out, George never teased him again. Perhaps George
recognizes in Lennie the simple yearning of all men for
friendship.