truth be told, they symbolize the marks of ownership.

first given to the princess by her true love years ago, she never took the collars off ever since. they very much hold a very personal attachment to her, the collars carries indeed great worth of gedrige's history — passed down from generation to generation. said collar consistently bearing a large, pink heart-shaped gemstone in the center. a one of a kind precious jewelry that has deep connection with the kingdom itself.

well... that is what the pygmy goat explains to others who asks, which is secretly a half-truth. in reality, as stated beforehand ; they epitomize the sign of ownership and domination, in her relationship{s}. while the princess favors light pink lace collars, she owns a variety of other ones. all permanently possessing a gold ring, to equip gems, bells, silk bows, and of course leashes. despite the truth being very raunchy — pretty much linked to bdsm, they are a sign of royalty as well. it gives her a sense of protection, knowing that she belongs to her one and only.

so what's the reason she gives that half-truth explanation? obviously, being exceedingly embarrassing for her to tell.