笑话理解之scissor&run

What's the difference between children and lesbians?

Children shouldn't run with scissors and Lesbians shouldn't scissor with the runs

这Joke有点dirty，也有点难以理解。

理解的关键在于需要知道 scissor 是剪刀，但同时也是一种 sex position (大致可以想像一下，剪刀状的)

而 runs 除了跑，还有腹泻的意思。