Humiliating

My wife and I have been experimenting with cuckolding for a few months. She has been with several other men while I have watched and jerked off. It is a huge thrill to see her have so much pleasure from another man. She has been with one particular guy several times and he is an experienced black bull for cuck couples. Now that they are more comfortable around each other they have increased the humiliation factor. One thing I find very humiliating is how I am made to cum. They will have me watch and then when I am going to cum I am made to cum on the floor in front of my seat. He will then finish fucking her and cum inside her. They walk over and will stomp on the wet spot in front of me. He enjoys that he is getting to cum inside my wife while my cum is being stomped under his feet. They have also made me cum in the toilet and flushed it. They heavily talk about how my cum is useless and needs to be wasted.