I have exactly the same sph fetish and I have been laughed at and turned down by women because of my penis size and I loved it. It was actually better than getting to have sex with them in some ways
Definitely like to have the sex but I know exactly what you mean. The vicarious thrill of a humiliating rejection is hugely arousing.
It is not a bad compensation for what would otherwise be simple dejection and disappointment.
I actually put myself in a situation knowing full well a woman I flirted with was a definite size queen (don't recall her name but I will refer to her as Maria who was the first girl who ever rejected me )
I knew one of her one night stands (Dave) as he was a member of a band I was a regular soundman/roadie for.
He had hooked up with Maria at an after gig party. She shared her disappointment with a couple of her mates by complaining he had a tiny cock. He found out about her malicious gossip because he tried to chat up one of those girls at a gig a week or so later.
The girl just laughed at him and said her Maria had told her he had a tiny penis while making the thumb and forefinger gesture.
I witnessed this as I was well within earshot and eyesight.
As it goes I crossed paths with Maria at another post gig party and she recognised me as the soundman and chatted me up. I was well aware that I would most likely get the same treatment as Dave but decided to go for it. It was kind of a win win situation as I might just get off with her and/or chastisement about my tiny dick.
I didn't get to fuck her as she pretty much laughed me out of the room when I got my pants off. (Actually she left in a huff because it was my hotel room)
It had got as far as her in her bra and panties and me just in a t shirt. She got one look at my babysized softie and decide she didn't need to participate any further. She uttered something like 'You've got to be kidding ! ' Put her clothes back on and barked at me about wasting her time while rushing out the door.
I only wished she could have stormed back in and saw me pulling on my pathetic 4" erection and gave me some more demeaning verbal.