This spell creates an invisible saddle made of force on a mount touched. No mount is conjured by this spell nor are any effects conferred upon the mount. First, the rider cannot be knocked off the mount unless willing to dismount. Second, dismounting is a reaction that does not require any movement. Third, the rider automatically passes any ability checks related to riding a mount, such as concentration checks to maintain spells during a vigorous ride. 

If you target a hostile or unwilling creature, that creature must succeed on a Dexterity saving throw to avoid the spell.