I went through a time where I actively sought bi encounters to compare my dick to bigger men. I had about a dozen opportunities where I was able to do the side by side like in some of the pictures others posted. I had (have) severe envy for bigger, thicker cocks... especially THICKER! A few even let me take pictures.
Once I saw and felt a real big, meaty phallus, I was hooked! It looked and felt so impressive... the heft and weight of a thick shaft felt so cool compared to my own slender one. I couldn't see how anyone would be happy with what I was packing. Fortunately, my new girlfriend has changed that thinking lately!