I did it! This is the first time I've popped a balloon. I was wearing heavy ear protection, but it's still an achievement for me.
It was a Q11 printed balloon. (Sent to me by Vicci when I bought something).
I inflated it to almost rated size and pinched the neck closed. Then I gently lowered myself on it. I pulled the lip to try to get a neck to form. I had to bounce a bit and before long I had a fully inflated neck. I wanted it to pop quickly so I would know how loud it would be so I bounced as hard as I could. It didn't pop. I kept bouncing, harder and harder, even digging my nails in at some point. Eventually I managed to pop it. I only heard a muffled snapping sound. I got another, a dark blue one this time. I inflated it to about 80% rated size but stopped because I thought I saw a defect. It was a discolouration on the side of it. I sat on it but it didn't pop, so I put some more air in. Then I bounced gently, trying to get the biggest neck possible. I tugged on the lip as hard as I could and lowered my whole weight onto the balloon. The neck was almost a foot long! I kept bouncing and stretching it, making it even bigger. It couldn't of been a defect or it would have popped by now. I loved how tight it felt. I had never got a balloon this big before, I've always dreamed of necking a balloon this much and here I was doing it for the first time. I then put the lip in my mouth and squeezed it to feel the neck touch my lips. That almost sent me over the edge. I almost blew into it but got too nervous unfortunately. I starting riding it next, surprised by how much it could take.
After a while of playing with it I let myself orgasm. I decided to keep it for next time and deflated it.