These soft, textured covers started as a means to enhance oral sex. Nowadays, some people like to wear them for the look, rather than their practical use. Unsurprisingly, the most common way to wear them is still in a tongue piercing.
Koosh beads are like ticklers. The biggest difference is that a koosh’s silicone can’t be removed from the inner bead. Koosh beads work in any piercing, and were most common on earrings in the 2000s.