In the interest of developing a mentally healthy way of integrating diapers into my life, without letting diapers take over my life, I explore this concept of "diapers as souvenir". I think this applies more to people who enjoy the safety, security, regression aspects of diaper wearing, and not so much the sexual attraction to them.
Years ago I took a vacation to the French island of Martinique. It was fabulous; I want to go back some day. Like a typical tourist, I bought a souvenir, a small box containing an assortment of locally grown spices. What a perfect souvenir. In my mind, those spices "smelled" like Martinique. I kept them for years, and any time I smelled them, it brought back that experience with great emotional clarity. However, it was obvious to me "what" was brining me joy - not the spices themselves - but the memory of that wonderful vacation.
I apply this concept to my own joy of wearing diapers. The texture, the sound, and smell of diapers (with baby powder added) awakens those feelings from my past life very strongly. Unfortunately, it is too easy to begin to take pleasure in the "thing" itself, and not the memory it evokes. This is the point where diapers begin to take on an unhealthy dimension, when you become obsessed with them alone.
I'm sure that, to the citizens of Martinique, there was nothing special about those spices. In fact, they may find it funny how much money we Americans pay for ordinary "weeds" that grow everywhere. Likewise, if you have ever experienced being around young children in diapers, it may surprise you that they hardly notice or care about them. I diaper is just an article of clothing, nothing special. I must believe that before I was potty trained, diapers meant almost nothing to me either.
The main thing I notice about "actual" children, is their enthusiasm for life. Their drive to explore and play and move nonstop. They are energized because life is so exciting for them. They hit the ground running every morning (no need for coffee and a shower to wake up), and go full speed until they collapse at nap time then again at night. THIS is what I want to be again - the feelings and energy that I yearn for. I want to be that Super Energized Toddler bursting with energy. Diapers are my souvenir for THAT.
I hope this is helpful to someone.