Contra corners is actually fairly easy in a set of three! This dance can be done with inexperienced dancers. It also can be done "genderfree," without regard to who's on which side of the set, though having a line of women and a line of men helps to make the contra corners clearer.
To "cast off to the invert the line," the top dancers in each line go down the outside to the bottom, the middle dancers follow them and loop around to return to middle place, while the third dancers follow and remain at the top.
||(8) Lines of three, forward and back|
(8) Top (active) couple goes down the center and casts up to middle place
||(16) Active couple turns contra corners
||(16) All balance & swing partner
||(8) Cast off to invert the line|
(8) Do-si-do partner