Embedding pins in polymer clay is a great way to add a finding without having to put a hole in your shape. The trick to making sure the pin stays in and never pulls out is the end being inserted into clay cannot just be a straight pin. If there isn’t anything for the clay to hold onto, the pin will eventually come out of the clay, even if you add superglue or other types of adhesives. It needs to have a loop, a bend, or something that will get ‘stuck’ in the clay. Headpins work great for this as

Embossing Polymer Clay with Silicone Druzy and Inlays