Possible Clues:

• Not sidesaddle
• Sitting normally, as on a horse
• One way to sit on a horse
• With legs stretched apart
• Dater's plus one all over the place, with a leg on either side!
• Like beginning of the journey on a horse perhaps
• Riding apace
• Like this, when finally sat on horse?
• Either side of
• Sat upon a long step