Here are many of the things I thought about, not all are included in this list.
Mistress tying me face down and spanking me with a cane until I used a safe-word. My goal would be to get her to quit before me. I'd dreamt about my ass being bruised and feeling it every time I sat down for a few days.
I got super hard thinking of Mistress making me suck a dildo until I used safe-word. I thought about her either using a strap-on or just using her hand, but I would be restrained and she would force the cock in my throat until I gagged. I thought of getting all sweaty, having tears running down my face and drool dripping out of my mouth and even my nose. I thought feeling like I was going to get sick. Feeling my jaw get exhausted. Knowing I would have a sore throat the next day. I tried finding a good picture, but all the good ones were of women with a dildo or real cocks. They had tears running down their faces. Their makeup was a mess and they had a total look of surrender on their faces. I fantasized about feeling like that. Here is the best male sub pic I could find.
I thought about a long painful tease and denial session. One that would have Mistress having orgasm after orgasm while I got none. She would get me to "confess" more and more things I would do just to have an orgasm. Then I imagine it ending one of a few ways. Mistress making me cum inside her and making me eat it out of her. Mistress rolling a condom on my cock and either using the hitachi on me or fucking me with the condom on. Then she would unroll the condom and make me eat all of my cum.
I fantasized about Mistress picking out more of my clothes on a whim. For example, one day she might say "let me see your underwear". Then she would make me go change them. Or she might make me wear something the back yard that borders on feminine. Of course there is always nightwear as well.
I also fantasized about Sophia getting a professional makeup/boudoir session. Based on some of the transformation jobs I have seen I can only imagine how Sophia would look. Of course, the humiliation of having someone else see me this way would only add to the excitement.
That's kind of it in a nutshell. I certainly had many other naughty thoughts over 5 mornings of being hung over. These are the ones that stick in my mind.