The chair is danced from promenade position using normal waltz timing 123 or SQQ in quickstep and foxtrot.
On 1: both partners step through with the inside foot with a checking action onto a bent knee. The flexing of the knees is similar to dancing a contracheck.
On 2: recover weight to back foot.
On 3: man RF back, lady LF fwd - slip pivot.
Alternatively,
On 3: man close RF to LF without weight, lady close LF to RF. Follow with same foot lunge.