There's a zillion things to be said about bits and gags, and I'm certain, that you could make an entire website on this topic.
Hére i'll limit myself to addressing a few good advices, mainly regarding safety.
Basicly there's a sries of demands, to a good 'shut-up-machine'...
1/ They cannot be 'chewable', meaning that there can be no possibility, that
they can be chewed into pieces.
2/ They cannot be able to frawn.
3/ They must be waterproof.
4/ They cannot have the posibility to ruin the teeth.
There's a long line of bits and gags available, and most of them are
fortunatelt OK.
If you, like I do, want to save quite a few bucks, and thus buy your bits in the
local "Rider-store", and not in a sex-shop, there's a series of fine
rubber-bits to choose from.
However, when we get to the steel bits, things get a little more complicated!
Steel and teeth is, and has always been, a bad combination. If the wearer bite
fiercely into a steel bit (either in great pain, and/or in case of an orgasm)
the possible result could be broken teeth. It's not only the size of the
dentist's bill afterwards, which make this an bad idea, but also the fact, that
it hurts like [...] !
The bit, that you see here, is the one, which I call a 'tounge-stopper-bit'.
The point is, that the gadget in the middle will depress the entire tounge,
depriving the user of the option to utter anything remotely sounding like a
word.
I have chosen, to modify the bit a little, by sewing two leather-pieces around
the bit, where it might get into contact with the teeth, upon which I have put
the bit into water (before applying grease to the leatyher).
What happens is, like you can see, that the leather is contracting, to give a
perfect fit, around the bit.
This to show, that it actually works nicely !