My horse wouldn't appreciate your atempts at that.
And mares tend to express their displeasure in such matters by kicking the snot out of the object of that displeasure. I saw it happen to our little stallion who was trying to mount a mare that was considerably larger than him, and while he was on a rope stacked to the ground. Without the rope, he'd have gotten the job done most likely. As it was, he got the hooves.