He also wants a " button fly." A " button" is what you use to connect two pieces of clothing.

他还想要一个“纽扣门襟”。 “纽扣”是用来连接两件衣服的东西。

Russell, then, wants a button fly; he wants a fly in the front of his underwear that has a button to keep it closed.

那么， 拉塞尔想要一个纽扣飞翔；他想要在内裤前面有一个门襟， 并有一个纽扣来保持闭合状态。