The ability to kiss with one's head canted in either direction with equal proficiency and skill.
She was only comfortable kissing with her head tilted to the left, so being ambineckstrous, I flopped my head over to the other side and kissed her till the moon blushed.
One who is ambidickstrous is able to Choke the chicken with the right hand while in the shower or spank the monkey with left the hand while on the computer, thus freeing your right hand to use the mouse. Plus it's like knowing two ladies.