Airplane bath is a quick method of cleaning by taking a wet wash cloth under "each wing" and "the tail"; meaning the armpits and the crotch region¹.

 

“飞机洗澡法”是一种快速洗澡方法，即用湿毛巾在两腋和胯部区域擦一下完事。

 

Example:

 

Dude 1: Hey, are you going out with us tonight?

Dude 2: Yeah, man. When?

Dude 1: In about five minutes.

Dude 2: Oh shit! I'll just take an airplane bath and go!

甲：嘿，你今晚和我们一起出去吗？

乙：当然了。啥时候啊？

甲：大约五分钟后。

乙：什么！我去“飞机洗澡”一下就走！