There are several definitions floating around out there - but this is an original scenario and should be considered an authentic Cactus
Jack henceforth -
If
lonely in the desert, take a small cactus and carefully remove all needles. Insert a knife in the
bottom and hollow out the pulp. You should now have a flap of cactus skin with a nicely lubricated, aloey, gooey lining. Carefully insert two fingers and feel around the inside looking for any "ingrown needles". Once satisfied that your cactus meets all safety requirements, you may proceed to have
sex with it. Afterwards, rinse and repeat as desired. The flap
will fold easily and can be kept discreetly in your pocket.
When
Casey was doing infantry training out in the desert, I heard he got
lonely in his fighting hole and made himself up a nice little Cactus
Jack for company.