stuffing your testes inside you is some advanced tucking magic that i never figured out, it's hard enough coaxing the balls through the cockring and putting on an inverted cage on without getting a boner
i wish I could wear metal inverted ones or even just nubs because they're so aesthetic and cute but my allergy to mystery chinesium metals (nickel?) would give me horrific seb derm, those "stainless steel" catheter inserts are always metal and that sucks
plastic is comfy tho, you literally forget it's there cus it's so light, plus metal ones rarely come with an assortment of cock ring and inverted insert sizes, you have to know what you want already
i think someone here asked how inverted cages work and how they're not self-harm, if you get a boner in them it just expands inside of you but only to an extent, you really can't hurt yourself or cause damage because the tissue is soft and squishy when flaccid