The slave lies on a high bench, ready for to be the saddle for Yvette and Adriana.
First Yvette mounts his belly like a horse and animates Adriana to sit in front of her on his throat.
They adjust their positions until it's comfortable for them and he has to endure their full weight.
Switching places seekeing better saddle... soon they lands with their asses on his face.
A face might be a good saddle but the lack of air?!?