The rare disorder of having two dicks, and sometime, one testicle, making threesomes a shit ton easier, and allowing extreme pleasure from double blowjobs.
Guy #1: I heard Kim Kardashian had sex with an Ambidickstrous guy...
Guy #2: Nah, if she did we would have gotten another sex tape.
Having the ability to masturbate with both hands.
When Dan's arm was in a cast, he had to learn to become ambidickstreous if he wanted to jerk his meat.