Hmmm....Gosh, there were so many "starting points" for me as a kid...Pluto, Winnie the Pooh, Alice in Wonderland, Sneezy, and other cartoon characters, but I think the one that really got me into sneezing was Dumbo. His sneeze after the elephant matriarch tickles his trunk is so adorable. Since he's a newborn, you can tell from his expression as the sneeze starts that he doesn't exactly know what to make of the tickly feeling in his tiny trunk, but that he probably enjoys it...and then he goes through the cutest soft, hiccuping buildups as his trunk curls up, and then relaxes and gives a big smile when the sneeze suddenly backs off, which is also cute. And then when he finally does sneeze, his adorably large ears come popping out.
Also, there was this time when I was about 5 years old and my dad took me and one of his university students to this play for little kids acting out the Dr. Seuss story "Green Eggs and Ham." There was this scene when the object of Sam - I- Am's relentless (and annoying) pursuit (who happened to be female in this version) finally agreed to try the green eggs and ham with the promise that Sam- I - Am will leave her alone. In the play I saw, as Sam held out the platter of green eggs and ham for the anthro dog to try, this huge pepper shaker was slightly lowered down from the gaffing up above, and hovered right over the dog about to eat the eggs and ham (is the character who gets followed around by Sam-I-Am supposed to be an anthro dog of some kind? I never could tell).
Even as a little kid, I remember seeing that big pepper shaker come gliding in and knowing EXACTLY where this was headed. Sure enough, The dog (I have no idea if the dog in the story ever had a name or not, so I'm just going to call her "Lafawndah" from this point on xD). So, there was this huge pepper shaker in the sky that was essentially raining pepper down on Lafawndah, and her eggs and ham, and she started to build up really dramatically: "AaaaHhhhh....AAAAAaaaahhh....AAAAAAAaaaahhh...." but I can't remember if she ever finished the sneeze or not. Anyway, I just remember that precise moment as when I realized at the tender age of 5 that I had a "thing" for sneezing. I lacked the proper vocabulary for it, but somehow I just knew what it was.