... from a purely literary standpoint, is that you can use almost any word to refer to them, and in the right context, people will know just what you mean. Substitutions are especially effective if they pertain to something roughly longer than it is wide. Dad found his remote, ya know what I'm sayin'? The lab assistant grabbed his beaker. My dentist had the biggest drill I've ever seen in my life.
The last verse I posted, Wee Willie's Winkie, uses ten different terms for the male member.