They are Wilson blue hand or paddle balls... come in a 3 pack.. in the sporting good dept. Very flexible but stiff.. Take an Xacto knife and cut a hole large enough to fit over your nipple... the take some sand paper and smooth the edges... apply some lubricant around the edge... squeeze and place it over you nipple... and release... it will suck your nipple in. to add more suction just squeeze it more in place and release.. I've been using them for months and they work
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