Wrangling the snake

This phrase means to "masturbate". As a snake is long, skinny and rounded like a penis. And wrangling means to tend or round up, which is what your are doing to the snake or your penis.

Guy 1: Hey girl mind wrangling the snake.
Female Snake Enthusiast: Wow really. Sure I'll do it, where is it at?
Guy 1: *whips out penis* Get to wrangling!