Locking Chain G-string

Try taking some vinyl tubing that just slides over the chain so that the links don't bite into her flesh. It will also make cleaning it a bit easier. I have one that I made - there are three strands of chain that attach together at the small of the back with two of them coming around my waist and one through my crotch, with a small padlock in front (or maybe you want it to be in back, where you have more control ).

You can also modify a dildo or butt plug with a ring (or a hole through it if long enough), so that the crotch chain can be slide through the hole/ring to hold the item in place. Although I have to tell you, when the chain is locked on tight, there is little room for anything to slip out of either hole.

Since some of it might be more wet then other parts you might wanna make sure the chain is water proof make sure its stainless and wont give allargy. One way to make sure that don't happen is to put on the chain over a pair of panties.

also you might want to add something somilar as is in these jewelry:

http://www.enchantedpleasures.com/sylvie-monthule-siren-g-string-with-clitoral-pendant