what causes you to "dump"

at 22 months I have never dumped and unfortunately tested the waters. The closest I have come was eating ice cream. It made me feel drunk. I had to lay still and have a nap for about an hour before the nauseousness passed. so, I guess I have dumped once. Other than that, nothing. I occasionally eat a handful (5-10) ju-jubes as a treat and they don't bother me. But other than that, I tend to not eat anything that has more than 10-12 g of sugar in it.