I had a brainspew here: http://daredevilkink.dreamwidth.org/6237.html?thread=11471453#cmt11471453 which is basically
'Matt is a human but believes he is a horse. Frank is the first human he's seen since his mother left him as a newborn to be raised by these intelligent horses. At the prompting of his adootive horse mother, Matt comes on to Frank with all his horsely charms. Frank is confused/turned on/confused'.
Matt/Frank. Crackish, pony play, pseudo-bestiality?
'Matt is a human but believes he is a horse. Frank is the first human he's seen since his mother left him as a newborn to be raised by these intelligent horses. At the prompting of his adootive horse mother, Matt comes on to Frank with all his horsely charms. Frank is confused/turned on/confused'.