I think I was 13. I was starting puberty but didn't know what to do about erections other than to wait for them to go away
At one point, I had a long latex balloon that I got from a birthday party or something. One day, I had a sudden urge to feel my cock against it when I had a boner. The balloon was slightly deflated, so it was flexible enough for me to wrap it around my cock one full time. With the ends in each hand, I'd pull it tighter and loosen it, tighter and loosen, over and over. I felt like an idiot since I didn't know why I felt compelled to perform this strange action, but it felt really good. And it kept feeling better the longer I did it. I liked the rubbery feeling and the latex squeaks. After several minutes, my cock started twitching and started spilling cum out the front. The sensation was wonderful
I've had ample opportunities to get off with a balloon since. But I think that it has a connection to my interest in diapers. Both are playful, yet embarrassing to enjoy. Diapers also expand and inflate, and also look balloonish when paired with plastic pants, giving them a thick and marshmallowy look. Though there are a lot of other reasons why diapers are exciting though. It took me a while to really connect my interests (I started discovering an interest in crossdressing in my early teen years which developed into sissy AB/DL stuff later on), but I don't want to start rambling