WOW! I love this threat. I am very much into cock comparisons. Especially when one guy is much MUCH bigger soft than the other is in full erection!
My first "experience" was with my cousin when I was 14 and he was 13. And yet, he was much bigger than me. He was bigger soft than I was in full erection! And since then I have always really been turned on by the idea that some guys being so huge even soft, while I am so small even hard.
Lucky for me, my wife (yes I am straight) had an EX who was massive, and references to his monster cock have now become a central part of our sex life.
I discovered about the Ex's huge size the first time my wife (then girlfriend) performed oral sex on me. She deep-throated SOOO easily that I asked: "wow, where did you learn to do this?" and she casually responded: "I have had a lot of practice on a rather more challenging cock".
I guess most guys would have been insulted by this comment, but not me. I was really turned on. So I asked: "Do you mean to say that Kevin was really big?" I knew Kevin from when they were together, and he was a rather small man. So I was really turned by the idea of this small guy being really big (this goes back to my "cousin experience". My cousin was smaller than me physically but much bigger sexually).
She looked at me before answering; she saw that I was really turned on, and smiled as she said: "Yes. Kevin was huge actually." Then I asked her to show me how big he was, and she showed me. Putting her hand around my cock, she showed me how thick he was. I asked her to give me a handjob as though I had Kevin's cock. So she did the gesture as though she was masturbating a huge, amazingly thick cock. I was so turned on.
"Was he really that big?" I asked? "Yes!". "Really?". Yes "yes really." And the I thought of all the times I had seem her with little Kevin, wondering what she saw in him. And I got really turned on at the idea of his huge cock. Thinking that every time I saw him he had this huge cock in his pants and that's why she was with her: because he could give her incredible orgasms with his massive penis. I was so turned on I came on her hand. I just love the feeling of her giving me a handjob as though I was three times a thick as I am. Paradoxically, what turns me on even more, is that she left him and his massive penis for me - and my tiny cock. And she knew what she was getting into when she left him for me, because for a few months, we had started sleeping together. And I would always ask her how was to go back to his monster after having been with me. And she would give me all sort of details on how amazingly different it was having his perfect big cock inside her, compared to my fragile little dink.
She broke up with him (the amazing cock was the only could thing about him). But still to this day, almost every time we have sex she tells me about how huge Kevin was. How he could make her cum in 30 seconds. How he would shoot his huge load inside her, or all over her face or all over her big breasts.
I have been trying to convince her that we should have Kevin over for a little 3-some. I would love to see his big cock next to my tiny thing. I would love to see him fuck her, and fill her up and then I could go inside her and she would not even fell me there. Or he could fuck her big pussy, while I fuck her ass (we very often have anal sex, because her pussy is too big for me and her ass feels much better - much tighter)
But she hasn't agreed to do it yet... Maybe some day.