They speak with forked tongues !
Because boys have one extra leg and girls have one extra mouth.
Because if there were one more, it'd be two forty. (Too farty) This works much better when spoken out loud. The joke how Irish people pronounce "forty."
A Reputable.
Because it's down to earth.
A boar constrictor !
Are ye alright in the back there lads?
A: "Use the fork, Luke."
Where there is a fork in the road. This and other tyre jokes here: